lexicon (n.) Look up lexicon at Dictionary.com
c. 1600, "a dictionary, a word-book," from Middle French lexicon or directly from Modern Latin lexicon, from Greek lexikon (biblion) "word (book)," from neuter of lexikos "pertaining to words," from lexis "word, a speaking, saying, speech, phrase; way of speaking, diction," from legein "to say" (see lecture (n.)).

Especially of dictionaries of Greek, Syriac, Hebrew, or Arabic, because these typically were written in Latin, and in Modern Latin lexicon (not dictionarius) was the preferred name for a word-book. The modern sense of "vocabulary proper to some sphere of activity" (1640s) is a figurative extension.
lexico- Look up lexico- at Dictionary.com
word-forming element, "pertaining to words or lexicons; lexical and," from Latinized form of Greek lexikos "pertaining to words" (see lexicon).
lexeme (n.) Look up lexeme at Dictionary.com
1937, from lexicon + -eme, ending abstracted from morpheme. Related: Lexemic.
lexical (adj.) Look up lexical at Dictionary.com
"relating to the vocabulary of a language," 1833, from a Latinized form of Greek lexikos "pertaining to words" (see lexicon) + -al (1). Related: Lexically.
lexicographer (n.) Look up lexicographer at Dictionary.com
"a dictionary-writer," 1650s, perhaps based on French lexicographe "lexicographer," from a Latinized form of Greek lexikographos, from lexikon "wordbook" (see lexicon) + -graphos "writer," from graphein "to write" (see -graphy).
Thaddeus Look up Thaddeus at Dictionary.com
masc. proper name, from Latin Thaddaeus, from Greek Thaddaios, from Talmudic Hebrew Tadday. Klein derives this from Aramaic tedhayya (pl.) "breasts." Thayer's "Greek-English Lexicon of the New Testament" suggests the sense might be "large-hearted," hence "courageous." In the Bible, a surname of the apostle Jude, brother of James the Less.
weakling (n.) Look up weakling at Dictionary.com
1520s, coined by Tyndale from weak (adj.) + -ling as a loan-translation of Luther's Weichling "effeminate man" (from German weich "soft") in I Cor. vi.9, where the Greek is malakoi, from malakos "soft, soft to the touch," "Like the Lat. mollis, metaph. and in a bad sense: effeminate, of a catamite, a male who submits his body to unnatural lewdness" ["Thayer's Greek-English Lexicon of the New Testament"].
delirium tremens (n.) Look up delirium tremens at Dictionary.com
1813, medical Latin, literally "trembling delirium," introduced 1813 by British physician Thomas Sutton, for "that form of delirium which is rendered worse by bleeding, but improved by opium. By Rayer and subsequent writers it has been almost exclusively applied to delirium resulting from the abuse of alcohol" [Sydenham Society Lexicon of Medicine]. As synonyms, Farmer lists barrel-fever, gallon distemper, blue Johnnies, bottle ache, pink spiders, quart-mania snakes in the boots, triangles, uglies, etc.
waive (v.) Look up waive at Dictionary.com
c. 1300, "deprive of legal protection," from Anglo-French weyver "to abandon, waive" (Old French guever "to abandon, give back"), probably from a Scandinavian source akin to Old Norse veifa "to swing about," from Proto-Germanic *waif- (see waif). In Middle English legal language, used of rights, goods, or women.
If the defendant be a woman, the proceeding is called a waiver; for as women were not sworn to the law by taking the oath of allegiance in the leet (as men anciently were when of the age of twelve years and upwards), they could not properly be outlawed, but were said to be waived, i.e., derelicta, left out, or not regarded. [from section subtitled "Outlawry" in J.J.S. Wharton, "Law-Lexicon, or Dictionary of Jurisprudence," London, 1867]
Related: Waived; waiving.
kaput (adj.) Look up kaput at Dictionary.com
"finished, worn out, dead," 1895 as a German word in English, from German kaputt "destroyed, ruined, lost" (1640s), which in this sense probably is a misunderstanding of an expression from card-playing, capot machen, a partial translation into German of French faire capot, a phrase which meant "to win all the tricks (from the other player) in piquet," an obsolete card game.

The French phrase means "to make a bonnet," and perhaps the notion is throwing a hood over the other player, but faire capot also meant in French marine jargon "to overset in a squall when under sail." The German word was popularized in English during World War I.
"Kaput" -- a slang word in common use which corresponds roughly to the English "done in," the French "fichu." Everything enemy was "kaput" in the early days of German victories. [F. Britten Austin, "According to Orders," New York, 1919]
French capot is literally "cover, bonnet," also the name of a type of greatcloak worn by sailors and soldiers (see capote).

The card-playing sense is attested in German only from 1690s, but capot in the (presumably) transferred sense of "destroyed, ruined, lost" is attested from 1640s (see William Jervis Jones, "A Lexicon of French Borrowings in the German Vocabulary (1575-1648)," Berlin, de Gruyter, 1976). In Hoyle and other English gaming sources, faire capot is "to win all the tricks," and a different phrase, être capot, literally "to be a bonnet," is sometimes cited as the term for losing them. The sense reversal in German might have come about because if someone wins all the tricks the other player has to lose them, and the same word capot, when it entered English from French in the mid-17c. meant "to score a capot against; to win all the tricks from," with figurative extensions, e.g.:
"There are others, says a third, that have played with my Lady Lurewell at picquet besides my lord; I have capotted her myself two or three times in an evening." [George Farquhar (1677-1707), "Sir Harry Wildair"]