Attractive model's daughter becoming Yale's principal (5)
I believe the answer is:
yummy
'principal' is the definition.
Both the definition and answer are adjectives. Perhaps you can see a link between them that I don't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for yummy that I've seen before include "That tastes great!" , "That's truly scrumptious!" , "Luscious" , "Very tasty" , "That tastes good!" .)