After
Old English æfter, of Germanic origin; related to Dutch achter .
wiktionary
From Middle English after, from Old English æfter, from Proto-Germanic *after, *aftiri, from Proto-Indo-European *h₂epotero-(“further behind, further away”), from *h₂epo(“off, away”).
Cognate with Scots efter(“after”), North Frisian efter(“after, behind”), West Frisian after, achter, efter(“behind; after”), Low German/Dutch achter(“behind”), German after-(“after-”), Swedish/Danish efter(“after”), Norwegian etter(“after”), Icelandic eftir(“after”), aftur(“back, again”).
The Irish usage to indicate recent completion of an activity is a calque of the Irish collocation Táim tar éis...(“I have just...”).
etymonline
after (adv., prep.)
Old English æfter "behind; later in time" (adv.); "behind in place; later than in time; in pursuit, following with intent to overtake" (prep.), from of "off" (see off (adv.)) + -ter, a comparative suffix; thus the original meaning was "more away, farther off." Compare Old Norse eptir "after," Old Frisian efter, Dutch achter, Old High German aftar, Gothic aftra "behind;" also see aft. Cognate with Greek apotero "farther off," Old Persian apataram "further."
From c. 1300 as "in imitation of." As a conjunction, "subsequent to the time that," from late Old English. After hours "hours after regular working hours" is from 1814. Afterwit "wisdom that comes too late" is attested from c. 1500 but seems to have fallen from use. After you as an expression in yielding precedence is recorded by 1650.
