mid-15c., "to strike so as to cause to make a short, quick sound;" intransitive sense "make a short, quick sound" is from 1570s; imitative. Of eyes, "to protrude" (as if about to burst), from 1670s. Sense of "to appear or to put with a quick, sudden motion" (often withup,off,in, etc.) is recorded from mid-15c. Baseball sense of "to hit a ball high in the air" is from 1867. Topop the question is from 1725, specific sense of "propose marriage" is from 1826. Related:Popped;popping.

"to or toward a point or place higher than another," Old Englishup,uppe, from Proto-Germanic*upp- "up," from PIE root*upo "under," also "up from under," hence also "over." As a preposition, from late Old English as "down onto, above and touching, sitting on, at the summit of;" from c. 1200 as "to a higher place."

Often used elliptically forgo up,come up,rise up, etc. To beup to (something) "engaged in some activity" (typically reprehensible) is by 1837. Slangup the river "in jail" is recorded by 1891, originally in reference to Sing Sing, which is up the Hudson from New York City. To drive someoneup the wall (1951) is from the notion of the behavior of lunatics or caged animals. Insulting retortup yours (scil.ass (n.2)) is attested by late 19c.

From the same Proto-Germanic source are Old Frisian, Old Saxonup "up, upward," Old Norseupp; Danish, Dutchop; Old High Germanuf, Germanauf "up;" Gothiciup "up, upward,"uf "on, upon, under;" Old High Germanoba, Germanob "over, above, on, upon."