Child and friend stone cold (7)
I believe the answer is:
totally
'child and friend stone cold' is the definition.
I can't judge whether this definition defines the answer.
'child and friend' is the wordplay.
'child' becomes 'tot' (term for a young child).
'and' says to put letters next to each other.
'friend' becomes 'ally' (an ally is a friend or supporter).
'tot'+'ally'='TOTALLY'
Can you help me to learn more?
(Other definitions for totally that I've seen before include "in every respect" , "Wholly" , "without reservation" , "without reserve" , "Altogether" .)