Adult joke with courage periodically recalled (5-2)
I believe the answer is:
grown-up
'adult' is the definition.
(I know that adult can be written as grown-up)
'joke with courage periodically recalled' is the wordplay.
'joke' becomes 'pun' (pun is a type of joke).
'with' becomes 'w' (short for with).
'periodically' indicates alternate letters (letters must be selected 'every so often').
'recalled' says the letters should be written backwards (to recall can mean to bring something back).
The alternate letters of 'courage' are 'org'.
'pun'+'w'+'org'='punworg'
'punworg' written backwards gives 'GROWN-UP'.
(Other definitions for grown-up that I've seen before include "Big" , "Adult" , "Fully developed person" , "Mature" , "Matured" .)