Old ship left first making slow movement (5)
I believe the answer is:
largo
'slow movement' is the definition.
(I've seen this before)
'old ship left first' is the wordplay.
'old ship' becomes 'argo' (I've seen this in other clues).
'left' becomes 'l' (common abbreviation).
'first' means one lot of letters go next to another.
'argo' after 'l' is 'LARGO'.
'making' acts as a link.
(Other definitions for largo that I've seen before include "Broad and slow (mus.)" , "Musically in slow tempo and dignified style" , "Key -, Humphrey Bogart film" , "Slow piece of music" , "Slow movement in music" .)