Level ground, with no rain, for Badminton competitor? (7)
I believe the answer is:
eventer
'badminton competitor?' is the definition.
(a horse in the Badminton Horse Trials)
'level ground with no rain' is the wordplay.
'level' becomes 'even' (synonyms).
'ground with no rain' becomes 'ter' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'even'+'ter'='EVENTER'
'for' acts as a link.
(Other definitions for eventer that I've seen before include "Equestrian horse" , "Showjumper" , "Competitive rider" , "Rider in contests" , "versatile horse" .)