Online Etymology Dictionary

admirer (n.): c. 1600, agent noun from admire (v.). "In common speech, a lover" [Johnson], a sense recorded from 1704.
admissibility (n.): 1763, from admissible + -ity.
admissible (adj.): 1610s, from Middle French admissible, from past participle stem of Latin admittere (see admit). Legal sense is recorded from 1849.
admission (n.): early 15c., "acceptance, reception, approval," from Latin admissionem (nominative admissio) "a letting in," noun of action from past participle stem of admittere (see admit). Meaning "an acknowledging" is from 1530s. Sense of "a literal act of letting in" is from 1620s. As short for admission price, by 1792.
admit (v.): late 14c., "let in," from Latin admittere "to allow to enter, let in, let come, give access," from ad- "to" (see ad-) + mittere "let go, send" (see mission). Sense of "to concede as valid or true" is first recorded early 15c. Related: Admitted; Admitting.
admittance (n.): 1580s, "the action of admitting," formed in English from admit + -ance (if from Latin, it would have been *admittence; French uses accès in this sense). Used formerly in senses where admission now prevails. Admissure was used in this sense from mid-15c.
admittedly (adv.): 1780, from past participle of admit + -ly (2).
admixture (n.): c. 1600, with -ure, from admix (1530s), a back-formation from admixt (early 15c.), from Latin admixtus "mixed with," past participle of admiscere "to add to by mingling, mix with," from ad- "to" (see ad-) + miscere "to mix" (see mix). In Middle English admixt was mistaken as a past participle of a (then) non-existent *admix. Earlier in this sense was admixtion (late 14c.).
admonish (v.): mid-14c., amonesten "remind, urge, exhort, warn, give warning," from Old French amonester (12c.) "urge, encourage, warn," from Vulgar Latin *admonestare, from Latin admonere "bring to mind, remind, suggest;" also "warn, advise, urge," from ad- "to" (see ad-) + monere "advise, warn" (see monitor (n.)).

The -d- was restored on Latin model. The ending was influenced by words in -ish (such as astonish, abolish). Related: Admonished; admonishing. Latin also had commonere "to remind," promonere "to warn openly," submonere "to advise privately."
admonition (n.): late 14c., amonicioun "reminding, instruction," from Old French amonicion "admonition, exhortation," from Latin admonitionem (nominative admonitio), noun of action from past participle stem of admonere "to advise, warn" (see admonish). Meaning "warning" is early 15c. The -d- was restored in English 17c.
admonitory (adj.): 1590s, from Late Latin admonitorius, from Latin admonitus, past participle of admonere "to advise, warn" (see admonish).
ado (n.): late 14c., "conflict, fighting; difficulty, trouble," compounded from at do, dialectal in Norse influenced areas of England for to do, as some Scandinavian languages used at with infinitive of a verb where Modern English uses to. For sense development, compare to-do. Meaning "fuss" is from early 15c. Also used in Middle English for "dealings, traffic," and "sexual intercourse" (both c. 1400).
adobe (n.): 1739, American English, from Spanish adobe, from oral form of Arabic al-tob "the brick," from Coptic tube "brick," a word found in hieroglyphics.
adolescence (n.): "age following childhood" (especially the period from the 15th to the 21st year), early 15c., from Middle French adolescence (14c.), from Latin adolescentia "youth," noun of state from adolescentem (see adolescent (n.)).
adolescent (n.): mid-15c., "youth, young man," from Middle French adolescent (15c.) or directly from Latin adolescentem (nominative adolescens) "growing, near maturity, youthful," present participle of adolescere "grow up, come to maturity, ripen," from ad- "to" (see ad-) + alescere "be nourished," hence, "increase, grow up," inchoative of alere "to nourish" (see old). Adolesce was a back-formed verb used early 20c. by H.G. Wells, G.B. Shaw, Louis MacNeice, but it seems not to have taken.
adolescent (adj.): 1785, from Latin adolescentem (nominative adolescens) "growing, near maturity, youthful," present participle of adolescere "grow up, come to maturity, ripen" (see adolescent (n.)).
Adolph: masc. proper name, from Old High German Athalwolf "noble wolf," from athal "noble" (see atheling) + wolf (see wolf (n.)). The -ph is from the Latinized form of the name.
Adonai: Old Testament word for "God," late 14c., from Medieval Latin, from Hebrew, literally "my lord," from adon (see Adonis) + suffix of 1st person.
Adonis (n.): "a beau," 1620s, from Greek Adonis, name of the youth beloved by Aphrodite, from Phoenician adon "lord," probably originally "ruler," from base a-d-n "to judge, rule." Adonai is the Hebrew cognate.
adopt (v.): c. 1500, a back-formation from adoption or else from Middle French adopter or directly from Latin adoptare "take by choice, choose for oneself, select, choose" (especially a child). Originally in English also of friends, fathers, citizens, etc. Sense of "to legally take as one's own child" and that of "to embrace, espouse" a practice, method, etc. are from c. 1600. Related: Adopted; adopting.
adoption (n.): mid-14c., from Old French adopcion or directly from Latin adoptionem (nominative adoptio), noun of action from past participle stem of adoptare "chose for oneself, take by choice, select, adopt," especially "to take into a family, adopt as a child," from ad- "to" (see ad-) + optare "choose, wish, desire" (see option (n.)).
adoptive (adj.): early 15c., from Middle French adoptif, from Latin adoptivus "pertaining to adoption," from stem of adoptere (see adopt).
adorable (adj.): 1610s, from French adorable, from Latin adorabilis "worthy of worship," from adorare (see adore). Weakened sense of "delightful, charming" is recorded from 1710. Related: Adorably; adorableness.
adoration (n.): 1540s, from Middle French adoration, from Latin adorationem (nominative adoratio) "worship, adoration," noun of action from past participle stem of adorare; see adore, the original sense of which is preserved in this word.
adore (v.): late 14c., aouren, "to worship, pay divine honors to, bow down before," from Old French aorer "to adore, worship, praise" (10c.), from Latin adorare "speak to formally, beseech, ask in prayer," in Late Latin "to worship," from ad- "to" (see ad-) + orare "speak formally, pray" (see orator). Meaning "to honor very highly" is attested from 1590s; weakened sense of "to be very fond of" emerged by 1880s. Related: Adored; adoring.
adoring (adj.): 1650s, "worshipping," present participle adjective from adore. Related: Adoringly.
adorn (v.): late 14c., "to decorate, embellish," also "be an ornament to," from Old French aorner "to order, arrange, dispose, equip; adorn," from Latin adornare "equip, provide, embellish," from ad- "to" (see ad-) + ornare "prepare, furnish, adorn, fit out," from stem of ordo "order" (see order (n.)). The -d- was reinserted by French scribes 14c., in English from late 15c. Related: Adorned; adorning.
adornment (n.): late 14c., "act of adorning;" also "a thing which adorns;" from Old French aornement "ornament, decoration," from aorner (see adorn).
Adrastea: "nemesis," daughter of Zeus, distributor of rewards and punishments, from Greek Adrasteia, literally "she from whom there is no escape," from adrastos "not running away," from privative prefix a- + stem of drasmos "a running away," related to dromos "course" (see dromedary).
adrenal (adj.): "of or near the kidneys," 1866, Modern Latin, from ad- + renalis "of the kidneys," from Latin renes "kidneys." Adrenal gland is from 1875.
adrenaline (n.): also Adrenalin (trademark name), coined 1901 by Japanese chemist Jokichi Takamine (1853-1922), who discovered it, from Modern Latin adrenal (see adrenal) + chemical suffix -ine (2). Adrenaline rush was in use c. 1970.
Adrian: masc. proper name, from Latin Adrianus/Hadrianus, literally "of the Adriatic" (see Adriatic).
Adriatic: sea east of Italy, from Latin Adriaticus, from town of Atria (modern Atri) in Picenum, once a seaport but now more than 12 miles inland. The name is perhaps from atra, neuter of atrum "black," hence "the black city;" or else it represents Illyrian adur "water, sea."
adrift (adv.): 1620s, from a- (1) "on" + drift. Figurative use by 1680s.
adroit (adj.): 1650s, "dexterous," originally "rightly," from French adroit, from phrase à droit "according to right," from Old French à "to" (see ad-) + droit "right," from Late Latin directum "right, justice," accusative of Latin directus "straight" (see direct (v.)). Related: Adroitly; adroitness.
adsorb (v.): 1882, transitive (intransitive use attested from 1919), back-formation from adsorption "condensation of gases on the surfaces of solids" (1882), coined in German from ad- + -sorption, abstracted from absorption. See absorb. Related: Adsorbent; adsorption.
adulate (v.): 1777, back-formation from adulation.
adulation (n.): late 14c., "insincere praise," from Old French adulacion, from Latin adulationem (nominative adulatio) "a fawning; flattery, cringing courtesy," noun of action from past participle stem of aduliari "to flatter," from ad- "to" (see ad-) + ulos "tail," from PIE *ul- "the tail" (source also of Sanskrit valah "tail," Lithuanian valai "horsehair of the tail"). The original notion is "to wag the tail" like a fawning dog (compare Greek sainein "to wag the tail," also "to flatter;" see also wheedle).
adult (adj.): 1530s (but not common until mid-17c.), from Latin adultus "grown up, mature, adult, ripe," past participle of adolescere "grow up, mature" (see adolescent). As a euphemism for "pornographic," it dates to 1958 and does no honor to the word.
adult (n.): "adult person," 1650s, from adult (adj.).
adulterate (v.): 1530s, back-formation from adulteration, or else from Latin adulteratus, past participle of adulterare "to falsify, corrupt," also "to commit adultery." Earlier verb was adulter (late 14c.). Related: Adulterated; adulterating.
adulteration (n.): c. 1500, from Latin adulterationem (nominative adulteratio), noun of action from past participle stem of adulterare "corrupt, falsify; debauch; commit adultery," from ad- "to" (see ad-) + alterare "to alter" (see alter).
adulterer (n.): early 15c., earlier avouter (c. 1300), avoutrer (late 14c.), agent noun from obsolete verb adulter "commit adultery; adulterate" (late 14c.), from Latin adulterare "to corrupt" (see adulteration).
adulteress (n.): late 14c., avoutresse, agent noun in fem. form from obsolete verb adulter (see adulterer).
adulterous (adj.): c. 1400, avoutrious "addicted to adultery," from obsolete verb adulter (see adulterer) + -ous.
adultery (n.): "voluntary violation of the marriage bed," c. 1300, avoutrie, from Old French avouterie (12c.), noun of condition from avoutre, from Latin adulterare "to corrupt" (see adulteration). Modern spelling, with the re-inserted -d-, is from early 15c. (see ad-).

In Middle English, also "sex between husband and wife for recreational purposes; idolatry, perversion, heresy." Classified as single adultery (with an unmarried person) and double adultery (with a married person). Old English word was æwbryce "breach of law(ful marriage)" (compare German Ehebruch). Adultery Dune in Arizona corresponds to Navajo sei adilehe "adultery sand," where illicit lovers met privately.
adulthood (n.): 1850, from adult + -hood.
adumbrate (v.): "to outline, to sketch," 1580s, from Latin adumbratus "sketched, shadowed in outline," past participle of adumbrare "to represent (a thing) in outline" (see adumbration). Meaning "to overshadow" is 1660s. Related: Adumbrated; adumbrating.
adumbration (n.): 1530s, from Latin adumbrationem (nominative adumbratio) "a sketch in shadow, sketch, outline," noun of action from past participle stem of adumbrare "to cast a shadow, overshadow, represent (a thing) in outline," from ad- "to" (see ad-) + umbrare "to cast in shadow," from PIE *andho- "blind, dark" (see umbrage).
advance (v.): mid-13c., avauncen, transitive, "improve (something), further the development of," from Old French avancier "move forward" (12c.), from Vulgar Latin *abanteare (source of Italian avanzare, Spanish avanzar), from Late Latin abante "from before," composed of ab- "from" (see ab-) + ante "before, in front of, against" (see ante).

The -d- was inserted 16c. on mistaken notion that initial a- was from Latin ad-. From c. 1300 as "to promote;" intransitive sense is mid-14c., "move forward." Meaning "to give money before it is legally due" is first attested 1670s. Related: Advanced; advancing. The adjective (in advance warning, etc.) is recorded from 1843.