Guard the wandering girl (8)
I believe the answer is:
daughter
'girl' is the definition.
('daughter' can be a synonym of 'girl')
'guard the wandering' is the wordplay.
'wandering' is an anagram indicator.
'guard'+'the'='guardthe'
'guardthe' anagrammed gives 'DAUGHTER'.
(Other definitions for daughter that I've seen before include "Relation" , "The guard (anag.)" , "Female offspring" , "Female child" , "'''Don't put your ... on the stage, Mrs Worthington'' (Noel Coward) (8)'" .)