Yellowish (6)
I believe the answer is:
sallow
'yellowish' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sallow that I've seen before include "Sickly yellowish colour" , "Sickly complexion" , "(Of a complexion) pale brown or yellowish" , "Pasty-faced" , "Of skin, yellowish in colour" .)