Looks for joins, say (5)
I believe the answer is:
seems
'looks' is the definition.
(I know this)
'joins say' is the wordplay.
'joins' becomes 'seams' (a seam joins two pieces of fabric).
'say' shows a homophone (sound like).
'seams' is a homophone of 'SEEMS'.
'for' acts as a link.
(Other definitions for seems that I've seen before include "Gives a certain impression" , "Appears, looks" .)