Descriptive word or phrase (7)
I believe the answer is:
epithet
This clue is a double definition.
'descriptive word' is the first definition.
(I've seen this before)
'phrase' is the second definition.
(an epithet is a descriptive phrase)
(Other definitions for epithet that I've seen before include "qualifier" , "title" , "nickname" , "Fitting description" , "Appellation" .)