Becoming a child (6)
I believe the answer is:
filial
'becoming' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for filial that I've seen before include "next generation" , "Relating to sons or daughters" , "Pertaining to a son or daughter" , "Child's (e.g. duty)" , "As befitting one's daughter or son" .)