Persuade commanding officer with a kiss (4)
I believe the answer is:
coax
'persuade' is the definition.
(to coax someone is to persuade them)
'commanding officer with a kiss' is the wordplay.
'commanding officer' becomes 'co'.
'with' means one lot of letters go next to another.
'kiss' becomes 'x' (X can represent a kiss).
'co'+'a'+'x'='COAX'
(Other definitions for coax that I've seen before include "Get round" , "Attempt to manipulate" , "Wheedle, persuade by flattery" , "Persuade; type of cable" , "Wheedle, cajole" .)