Young listener's age (3)
I believe the answer is:
ten
'age' is the definition.
(ten years old is an age)
'young listener's' is the wordplay.
'TEN' is hidden within the letters.
However, I am not sure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for ten that I've seen before include "No of sides of a decagon" , "Cardinal number" , "time" , "Very young" , "Five times two" .)