Male in carriage is forward (8)
I believe the answer is:
transmit
'is forward' is the definition.
(thesaurus)
'male in carriage' is the wordplay.
'male' becomes 'm' (common abbreviation).
'in' means one lot of letters goes inside another.
'carriage' becomes 'transit' (I've seen this before).
'm' inserted within 'transit' is 'TRANSMIT'.
(Other definitions for transmit that I've seen before include "Broadcast (a signal)" , "Send from one place to another" , "Pass or hand on" , "Send from one person to another, or broadcast" , "Communicate (an idea)" .)