Go off (7)
'go off' is the definition.
(as in food going off)
This is all the clue.
(Other definitions for rot that I've seen before include "Deterioration" , "Decay in grotesque way" , "Rubbish (colloq.)" , "SECOND PART OF 25" , "bunk" .)
'go off' is the definition.
(exploding is a kind of going off)
This is the entire clue.
(Other definitions for explode that I've seen before include "Burst outward" , "Set off" , "Burst violently" , "Violently shatter" , "Detonate" .)