sub

(noun): A submarine.
(noun): A submarine sandwich: a sandwich made on a long bun.
(noun): A substitute, often in sports.
(noun): (often in plural) A subscription: a payment made for membership of a club, etc.
(noun): A subtitle.
(noun): A subroutine (sometimes one that does not return a value, as distinguished from a function, which does).
(noun): A subeditor.
(noun): A subcontractor.
(noun): (BDSM) A submissive.
(noun): A subordinate.
(noun): A subaltern.
(noun): A subscription (or (by extension) a subscriber) to an online channel or feed.
(noun): Subsistence money: part of a worker's wages paid before the work is finished.
(verb): To substitute for.
(verb): To work as a substitute teacher, especially in primary and secondary education.
(verb): To replace (a player) with a substitute.
(verb): Less commonly, and often as sub on, to bring on (a player) as a substitute.
(verb): To perform the work of a subeditor or copy editor; to subedit.
(verb): To lend.
(verb): To subscribe.
(verb): (BDSM) To take a submissive role.

We can get subs at that deli.
She worked as a sub until she got her teaching certificate.
I've just noticed a mistake in the subs for this film.
I'm totally stoked; just got 10 new subs after my last video.
He never really made a contribution to the match, so it was no surprise when he was subbed at half time.