Actors on holiday begin a voyage (4,3)
I believe the answer is:
cast off
'begin a voyage' is the definition.
I can't judge whether this defines the answer.
'actors on holiday' is the wordplay.
'actors' becomes 'cast' (group of actors).
'on holiday' becomes 'off' (eg on holiday from work).
'cast'+'off'='CAST-OFF'
Can you help me to learn more?
(Other definitions for cast off that I've seen before include "abandoned" , "Discard" , "When the stage has emptied" , "Eliminate stitches - prepare for sea" , "unwanted garment" .)