Feeling hot, group goes topless (5)
I believe the answer is:
hunch
'feeling' is the definition.
(I know that hunch is a type of feeling)
'hot group goes topless' is the wordplay.
'hot' becomes 'h' (abbreviation eg on taps).
'group' becomes 'bunch'.
'goes topless' means to remove the first letter (I've seen 'go topless' mean this).
'bunch' with its initial letter taken off is 'unch'.
'h'+'unch'='HUNCH'
(Other definitions for hunch that I've seen before include "Bend over" , "Intuition, suspicion" , "Premonition; hump" , "Lump - intuitive feeling" , "Vague suspicion" .)