They’re much less dangerous when they stink (5)
I believe the answer is:
bombs
'they're much less dangerous when they' is the definition.
The definition suggests an adverb but the answer is not.
'stink' is the wordplay.
I cannot really understand how this works, but
'stink' could be 'bo' (body odour) and 'bo' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bombs that I've seen before include "Shells" , "Explosive devices" , "Fails horribly" , "Weapons" .)