Mixes thoroughly (6)
I believe the answer is:
blends
'mixes thoroughly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for blends that I've seen before include "Combines into one" , "Mixes together" , "Mingles, becomes a mixture or a whole" , "Mixes into one" , "Coalesces" .)