Like mayonnaise (6)
I believe the answer is:
creamy
'like mayonnaise' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for creamy that I've seen before include "Rich and smooth like milk product" , "Yellowish-white in colour like best of milk" , "A mercy (anag)" , "Like Guernsey milk" , "Rich like fatty part of milk" .)