Child attached to friend without reservation (7)
I believe the answer is:
totally
'without reservation' is the definition.
(I've seen this before)
'child attached to friend' is the wordplay.
'child' becomes 'tot' (I've seen this before).
'attached to' says to put letters next to each other.
'friend' becomes 'ally' (I've seen this before).
'tot'+'ally'='TOTALLY'
(Other definitions for totally that I've seen before include "Absolutely" , "perfectly" , "Wholly" , "in every respect" , "Clean" .)