Carry off sailor over channel (6)
I believe the answer is:
abduct
'carry off' is the definition.
(thesaurus)
'sailor over channel' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'over' says to put letters next to each other.
'channel' becomes 'duct' ('duct' can be a synonym of 'channel').
'ab'+'duct'='ABDUCT'
(Other definitions for abduct that I've seen before include "Take (someone) illegally" , "Remove by force" , "Criminally remove to an undisclosed location" , "Carry off illegally" , "Take (someone) away by force" .)