Perfectly match basin, say (4)
I believe the answer is:
sync
'perfectly match' is the definition.
'sync' can be an answer for 'match' (I've seen this in another clue). I am unsure of the 'perfectly' bit.
'basin say' is the wordplay.
'basin' becomes 'sink' (I've seen this in another clue).
'say' shows a homophone (sound like).
'sink' sounds like 'SYNC'.
Can you help me to learn more?
(Other definitions for sync that I've seen before include "Relationship when things occur at the same time" , "In which one's matching" , "In which things occur simultaneously" , "go together" , "Agreement in time" .)