Random greeting to Romeo by young lady (3,2,4)
I believe the answer is:
hit or miss
'random' is the definition.
(hit or miss can mean unpredictable or inconsistent)
'greeting to romeo by young lady' is the wordplay.
'greeting' becomes 'hi' (hi is a kind of greeting).
'romeo' becomes 'R' (phonetic alphabet: alpha, bravo, charlie etc.).
'by' says to put letters next to each other.
'young lady' becomes 'miss' (term of address for a young woman).
'hi'+'to'+'r'+'miss'='HIT-OR-MISS'
(Other definitions for hit or miss that I've seen before include "hard to predict" , "careless" , "not having consistent effect" , "Random" , "The only options for a gunman" .)