Skimpy underwear awfully hot, no good (5)
I believe the answer is:
thong
'skimpy underwear' is the definition.
(I've seen this before)
'awfully hot no good' is the wordplay.
'awfully' is an anagram indicator.
'no' becomes 'n' (common abbreviation).
'good' becomes 'g' (abbreviation).
'hot' anagrammed gives 'tho'.
'tho'+'n'+'g'='THONG'
(Other definitions for thong that I've seen before include "Narrow strip of leather (or other material)" , "Insubstantial underwear" , "G-string" , "Lash of whip" , "What offers little coverage" .)