Gallant American doctor contains problematic situation (7)
I believe the answer is:
admirer
'gallant' is the definition.
(thesaurus)
'american doctor contains problematic situation' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'doctor' becomes 'dr' (abbreviation).
'contains' is an insertion indicator.
'problematic situation' becomes 'mire' (mire can mean a complex or difficult situation).
'dr' placed around 'mire' is 'dmirer'.
'a'+'dmirer'='ADMIRER'
(Other definitions for admirer that I've seen before include "Romantic adorer" , "Suitor; devotee" , "girlfriend?" , "potential suitor" , "Fan or devotee" .)