Secret desire overwhelms Romeo (6)
I believe the answer is:
covert
'secret' is the definition.
(similar in meaning)
'desire overwhelms romeo' is the wordplay.
I cannot really understand how this works, but
'romeo' could be 'r' (phonetic alphabet: alpha, bravo, charlie etc.) and 'r' is found within the answer.
'desire' could be 'covet' (I've seen this before) and 'covet' is present in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for covert that I've seen before include "Hidden - thicket" , "Unacknowledged; thicket" , "Hidden, secret" , "Concealed, secret" , "Concealed like fox's liar" .)