Where does “instant” come from?

instant (Latin) comes from Latin insto, from Latin īn-, from Latin în, from Latin en, from Proto-Italic en, from Proto-Indo-European h₁én — in.

instant (Latin): third-person plural present active indicative of...

Definitions

Step	Language	Word	Meaning
1	Latin	insto	I stand upon, set foot on; I assail, press upon,...
2	Latin	īn-	un-, non-, not
3	Latin	în	in, at, on, upon, from (space)
4	Latin	en	lookǃ beholdǃ; reallyǃ?; come onǃ
5	Proto-Italic	en	in
6	Proto-Indo-European	h₁én	in