A dispute after day at sea (6)
I believe the answer is:
adrift
'at sea' is the definition.
(drifting at sea)
'a dispute after day' is the wordplay.
'dispute' becomes 'rift' (rift can mean a feud or dispute).
'after' means one lot of letters go next to another.
'day' becomes 'd' (abbreviation for day).
'rift' after 'd' is 'drift'.
'a'+'drift'='ADRIFT'
(Other definitions for adrift that I've seen before include "Wandering aimlessly" , "Disoriented" , "(Of boat) moving out of control" , "Floating freely, not moored" , "Floating unattached as at sea" .)