Transfer prisoner with a gesture (7)
I believe the answer is:
consign
'transfer' is the definition.
(thesaurus)
'prisoner with a gesture' is the wordplay.
'prisoner' becomes 'con' (abbreviation for 'convict').
'with' means one lot of letters go next to another.
'a gesture' becomes 'sign' (sign is a kind of gesture).
'con'+'sign'='CONSIGN'
(Other definitions for consign that I've seen before include "Hand over (to the Post Office?)" , "dispatch" , "A PM; a race since 1780" , "Commit or deliver formally" , "Give over to another" .)