On this side, you can see the joins (5)
I believe the answer is:
seamy
But I can't explain it at all! Could you help me understand?
(Other definitions for seamy that I've seen before include "Squalid" , "Marked with joins; disreputable" , "Sordid, disreputable" , "Sleazy, sordid" , "Disreputable (side)" .)