Being transient, it starts fading (3)
I believe the answer is:
fad
This might be a double definition.
'being transient' is the first definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'it starts fading' is the second definition.
The definition suggests a singular noun which matches the answer.
Can you help me to learn more?
(Other definitions for fad that I've seen before include "A craze or current vogue" , "A passing fashion or craze" , "Craze; idiosyncrasy" , "transient success" , "A passing liking or fashion" .)