check-up n.

late 15c., in chess, "to attack the king; to put (the opponent's king) in check;" earlier (late 14c.) in a figurative sense, "to stop, arrest; block, barricade;" from check (n.1) or Old French eschequier, from the noun in French. A player in chess limits his opponent's ability to move when he places his opponent's king in check.

The other senses seem all to have developed from the chess sense, or from the noun: "To arrest, stop," then "to hold in restraint" (1620s); "to hold up or control" (an assertion, a person, etc.) by comparison with some authority or record (1690s); of baggage, etc., "to hand over in return for a check that serves as a means of identifying" (1846); "to note with a mark as having been examined, etc., mark off from a list" (1928).

Hence, to check off (1839); to check up (1883); to check in or out (in a hotel, of a library book, etc., 1909). To check out (something) "to look at, investigate" is from 1959. Related: Checked; checking.

Old English up, uppe, from Proto-Germanic *upp- "up" (source also of Old Frisian, Old Saxon up "up, upward," Old Norse upp; Danish, Dutch op; Old High German uf, German auf "up"; Gothic iup "up, upward," uf "on, upon, under;" Old High German oba, German ob "over, above, on, upon"), from PIE root *upo "under," also "up from under," hence also "over."

As a preposition, "to a higher place" from c. 1500; also "along, through" (1510s), "toward" (1590s). Often used elliptically for go up, come up, rise up, etc. Up the river "in jail" first recorded 1891, originally in reference to Sing Sing, which is up the Hudson from New York City. To drive someone up the wall (1951) is from the notion of the behavior of lunatics or caged animals. Insulting retort up yours (scil. ass) is attested by late 19c.