One growing wild may intimidate trembling players (3,7)
I believe the answer is:
cow parsley
'one growing wild may' is the definition.
The answer and definition can be both plants as well as being singular nouns.
Maybe there's an association between them I don't understand?
'intimidate trembling players' is the wordplay.
'intimidate' becomes 'cow' (cow can mean to bully or intimidate).
'trembling' indicates anagramming the letters.
'players' anagrammed gives 'parsley'.
'cow'+'parsley'='COW-PARSLEY'
Can you help me to learn more?
(Other definitions for cow parsley that I've seen before include "Fragrant white wayside flower" , "Hedgerow plant" .)