sass Share definition Flag Attitude, mouthing off, not backing down to the man, putting the smack down, opening a can of Bruce Lee. 1.Don't you sass me missy. 2. I didn't want to put up with her crap, so I sassed her. sass by CSUID December 11, 2003 Words you can keep railfan mug chonk mug chud mug based mug 67 mug slime mug mogging mug chopped mug thot mug glazing mug huzz mug yams mug larp mug unc mug cracked mug simp mug baddie mug bop mug lolcow mug