Wrathful when grenade explodes? (7)
I believe the answer is:
angered
'wrathful' is the definition.
(I've seen this in another clue)
'grenade explodes?' is the wordplay.
'explodes?' indicates an anagram (I've seen 'explode' mean this).
'grenade' is an anagram of 'ANGERED'.
'when' is the link.
(Other definitions for angered that I've seen before include "Very annoyed" , "In high dudgeon" , "En garde (anag.)" , "Enraged (anag)" , "Infuriated" .)