Bard's lover Romeo, one mixing with louts (7)
I believe the answer is:
troilus
'bard's lover' is the definition.
'troilus' can be an answer for 'lover' (I have seen 'Lover of Cressida ' mean 'troilus' so perhaps 'lover' could also mean 'troilus'). I am unsure of the 'bard's' bit.
'romeo one mixing with louts' is the wordplay.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'one' becomes 'i' (Roman numeral).
'mixing with' is an anagram indicator.
'r'+'i'='ri'
'ri' anagrammed with 'louts' makes 'TROILUS'.
Can you help me to learn more?
(Other definitions for troilus that I've seen before include "Cressida's lover (Shak.)" , "Lover of 11 Down" , "Lover of Cressida (Shak.)" , "Cressida's partner" , "Title role" .)