Effort to welcome a Conservative girl (5)
I believe the answer is:
tracy
'girl' is the definition.
'effort to welcome a conservative' is the wordplay.
'effort' becomes 'try' (synonyms).
'to welcome' means one lot of letters goes inside another (inserted letters are welcomed in).
'conservative' becomes 'C' (UK political abbreviation).
'a'+'c'='ac'
'try' enclosing 'ac' is 'TRACY'.
(Other definitions for tracy that I've seen before include "Film actor" , "Spencer -, US actor" .)