Clothing for monks and nuns (6)
I believe the answer is:
habits
'clothing for monks and nuns' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for habits that I've seen before include "Customs or robes" , "Normal practices in nuns' clothing?" , "Uniforms of religious orders" , "Customs or monk's gowns" , "Monks' and nuns' clothing" .)