Laugh a little at the attire (5)
I believe the answer is:
habit
'the attire' is the definition.
(habit is a kind of attire)
'laugh a little' is the wordplay.
'laugh' becomes 'ha'.
'a little' becomes 'bit' (both can mean a small amount of something).
'ha'+'bit'='HABIT'
'at' acts as a link.
(Other definitions for habit that I've seen before include "Custom; clothing" , "Settled practice" , "Custom, nun's wear" , "Monk's robe or repetitive action" , "Monk's gown or custom" .)