Comfortable about weapons (4)
I believe the answer is:
snug
'comfortable' is the definition.
(similar in meaning)
'about weapons' is the wordplay.
'about' shows that the letters should be reversed in order.
'weapons' becomes 'guns' (gun is a kind of weapon).
'guns' in reverse letter order is 'SNUG'.
(Other definitions for snug that I've seen before include "He joined" , "joiner" , "Comfortable -- small secluded room" , "Intimate" , "Compact" .)