Calm down if embraced by girl (7)
I believe the answer is:
mollify
'calm down' is the definition.
(mollifying is a kind of calming down)
'if embraced by girl' is the wordplay.
'embraced by' means one lot of letters goes inside another.
'girl' becomes 'molly' (**).
'if' placed into 'molly' is 'MOLLIFY'.
(Other definitions for mollify that I've seen before include "Soothe feelings of" , "Placate, appease" , "Appease the anger of (someone)" .)