He disperses hot air for nothing (7)
I believe the answer is:
horatio
'he' is the definition.
'disperses hot air for nothing' is the wordplay.
'disperses' indicates anagramming the letters.
'for' is a charade indicator (letters next to each other).
'nothing' becomes 'o' (looks like zero - 0).
'hot'+'air'='hotair'
'hotair' anagrammed gives 'horati'.
'horati'+'o'='HORATIO'
(Other definitions for horatio that I've seen before include "- Nelson, British admiral" , "Shakespearean part" , "Speaker of Good night, sweet prince (Hamlet)" , "Nelson's given name" , "Nelson's first name" .)