A jacket shortened, very hot? (6)
I believe the answer is:
ablaze
'hot?' is the definition.
(thesaurus)
'a jacket shortened' is the wordplay.
'jacket' becomes 'blazer' (blazer is a kind of jacket).
'shortened' means to remove the last letter.
'blazer' with its last letter taken off is 'blaze'.
'a'+'blaze'='ABLAZE'
'very' acts as a link.
(Other definitions for ablaze that I've seen before include "On fire, burning" , "filled with anger" , "Well-lit" , "Flaming; on fire" , "Fiercely aflame" .)