1590s, "to put on," from get (v.) + on (adv.). Meaning "prosper" is from 1785; that of "to advance, make progress" is from 1798; that of "be friendly" (with) is attested by 1816.
gesundheit
get
get along
get back
get off
get on
get over
get-away
Gethsemane
get-out
get-rich-quick