also markup, "amount added by a retailer to cover overhead and provide profit," 1899, from the verbal phrase in this sense (by 1870); see mark (v.) + up (adv.).

"action of signing up; number who have signed up," 1940, from the verbal phrase meaning "to enroll, enlist," which is attested by 1903; see sign (v.) + up (adv.).

also coverup, "means or act of concealing" some event or activity, 1922, from the verbal phrase (1872), from cover (v.) + up (adv.).

from 1906 as a type of baseball hit; from pop (v.) + up (adv.). As an adjective from 1934 (of a children's book, later toasters, etc.).

"interior regions," 1680s, from up- + country (n.). As an adjective from 1810; as an adverb from 1864.

1882, from the verbal phrase; see write (v.) + up (adv.).

"a joining together or coupling," 1945, from the verbal phrase; see link (v.) + up (adv.).

1830 as the name of a children's game (OED describes it as "all-fours" when played for seven "chalks"); with capital initials, as the proprietary name of a brand of carbonated drink, it is attested from 1928.

"adjustments made to an automobile to improve its working," 1911, from verbal phrase tune up "bring to a state of effectiveness," 1718, in reference to musical instruments, from tune (v.) + up (adv.). Attested from 1901 in reference to engines. Meaning "event that serves as practice for a later one" is from 1934, U.S. sports jargon.

also cleanup, 1856, "act of cleaning up,  a general cleaning," from clean + up. Meaning "a profit" is recorded from 1878. Verbal phrase clean up "make a large profit" is from 1929. The adjective, in the baseball sense, is recorded by 1910 in reference to the hitter who bats fourth in the lineup: His job is to drive in runs by scoring the players who hit before him and thus "clean up" the bases.