"Delish!" (3)
(Other definitions for yum that I've seen before include "Mmm, delicious!" , "I like it!" .)
'delish' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for yummy that I've seen before include "Like delicious food" , "Very tasty" , "Delicious (colloq.)" , "That tastes great!" , "Mmmmmm!" .)