Adult getting cheeky again (6)
I believe the answer is:
afresh
'again' is the definition.
(synonyms)
'adult getting cheeky' is the wordplay.
'adult' becomes 'a' (abbreviation).
'getting' says to put letters next to each other.
'cheeky' becomes 'fresh' (I've seen this before).
'a'+'fresh'='AFRESH'
(Other definitions for afresh that I've seen before include "Anew, from the beginning" , "In a new way" , "In a different way" , "Newly" , "Academy award" .)