Slight regulars with no gear (4)
I believe the answer is:
slur
'slight' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for slur that I've seen before include "Slight - mark on music" , "Insinuation; indistinct utterance" , "Mumble words - it's an affront" , "Negative comment" , "Pronounce indistinctly or smear" .)