Like grass? Ruddy yes, European admitted! (5)
I believe the answer is:
reedy
'like grass?' is the definition.
I can't judge whether this defines the answer.
'ruddy yes european admitted' is the wordplay.
'ruddy' becomes 'red' (synonyms).
'yes' becomes 'y'.
'european' becomes 'E' (abbreviation e.g. EU).
'admitted' is an insertion indicator (inserted letters are admitted in).
'red'+'y'='redy'
'redy' going around 'e' is 'REEDY'.
Can you help me to learn more?
(Other definitions for reedy that I've seen before include "(Of voice) high/thin" , "Grassed up" , "Piping, fluting" , "full of vegetation" , "(Of sound) high and thin" .)