Gruff adult suppresses rage (3)
I believe the answer is:
fad
'rage' is the definition.
('fad' can be a synonym of 'rage')
'gruff adult suppresses' is the wordplay.
'FAD' is hidden within the letters.
But, I'm uncertain how this is indicated.
Can you help me to learn more?
(Other definitions for fad that I've seen before include "A craze or current vogue" , "Short-lived craze" , "Temporary vogue or craze" , "A passing liking or fashion" , "Craze; idiosyncrasy" .)