Girl needing a new name missing in the morning (4)
I believe the answer is:
anne
'girl' is the definition.
'a new name missing in the morning' is the wordplay.
'a new' becomes 'an' (I've seen this in other clues).
'missing' suggests deleting specific letters.
'in the morning' becomes 'am'.
'name' with 'am' taken out is 'ne'.
'an'+'ne'='ANNE'
'needing' is the link.
(Other definitions for anne that I've seen before include "The Princess Royal" , "Female name" , "Shakespeare's wife's name" , "- Frank, World War Two diarist" , "Queen 1702-1714" .)