Whilst tight, laugh about hot pants (8)
I believe the answer is:
although
'whilst' is the definition.
(I've seen this before)
'tight laugh about hot pants' is the wordplay.
'tight' indicates an anagram (tight can mean drunk).
'about' is an insertion indicator.
'pants' indicates an anagram (UK informal term for 'nonsense' or 'rubbish').
'laugh' is an anagram of 'alugh'.
'hot' is an anagram of 'tho'.
'alugh' going around 'tho' is 'ALTHOUGH'.
(Other definitions for although that I've seen before include "Hugo, halt! (anag)" , "Apart from the fact that" , "Whilst" , "Notwithstanding" , "Yet" .)