Field dismal without young man — top player (7,4)
I believe the answer is:
leading lady
'top player' is the definition.
(top actor or player)
'field dismal without young man' is the wordplay.
'field' becomes 'lea' (lea can mean a meadow or field of grass).
'dismal' becomes 'dingy' (dingy can mean dark or dismal).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'young man' becomes 'lad' (lad can mean a boy or young man).
'dingy' going around 'lad' is 'dinglady'.
'lea'+'dinglady'='LEADING LADY'
(Other definitions for leading lady that I've seen before include "Film" , "Actress with principal part" , "Heroine - gaily landed (anag)" , "Queen Elizabeth II?" , "a star" .)