Cordial but not popular? One may blow up (7)
I believe the answer is:
grenade
'one may blow up' is the definition.
I can't judge whether this definition defines the answer.
'cordial but not popular?' is the wordplay.
'cordial' becomes 'grenadine' (I've seen this before).
'but not' is a deletion indicator.
'popular?' becomes 'in' ('in' can mean trendy).
'grenadine' with 'in' taken away is 'GRENADE'.
Can you help me to learn more?
(Other definitions for grenade that I've seen before include "ultimate weapon" , "Enraged (anag)" , "Hand-thrown bomb" , "One might go off" , "Hand-thrown explosive" .)