"... ___ quit!"

ORI

Think of a short phrase that means "never give up" and sounds like a name.

This clue is a fill-in-the-blank for the phrase "or I quit," which sounds like the name "Ori" when spoken aloud. The wordplay relies on the homophone trick—"or I" and "Ori" sound identical, so the answer is the three-letter name that fits both the blank and the pun. It’s a common crossword device where pronunciation overrides spelling.