In front of sink, see red sandal (4-4)
I believe the answer is:
flip-flop
'sandal' is the definition.
(I have seen 'Flimsy sandal ' mean 'flip-flop' so perhaps 'sandal' could also mean 'flip-flop')
'in front of sink see red' is the wordplay.
'in front of' is a charade indicator (letters next to each other).
'sink' becomes 'flop'.
'see red' becomes 'flip' (I've seen this before).
'flop' after 'flip' is 'FLIP-FLOP'.
(Other definitions for flip-flop that I've seen before include "Shoe held on by a toe-thong" , "Rubber-soled sandal" , "Light shoe" , "Flimsy sandal" , "Sandal held on by a toe-thong" .)