Gum unit (5)

I believe the answer is:

stick

(Other definitions for stick that I've seen before include "heavy criticism" , "Staff - criticism" , "Switch < put up" , "Join firm" , "School punishment once" .)

I've seen this clue in The Wall Street Journal.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.