Stephen A. Smith: I Won't Fight Glenn Robinson ... And I Apologize, Sorta.

Put down your popcorn ... Stephen A. Smith says he will NOT accept Glenn Robinson's invitation to fight him in a MMA cage match -- after Glenn called him out on "TMZ Sports."

Smith just appeared on "First Take" and actually APOLOGIZED to the former NBA star for dragging him back into the headlines by going public with their decade-long feud on a radio interview last week.

But it wasn't all sunshine and rainbows ... Smith made it clear the two sides hate each other -- will ALWAYS hate each other -- and he insists the allegations he made about Robinson being a racial hypocrite are 100% true.

As for the offer to fight it out once and for all ... Smith says "the street in me" wanted to handle it one way ... but the "grown man" in him convinced him to go another direction.

Smart move ...

Check out the "TMZ Sports" TV show weeknights on FS1.