Bothering single Romeo with card (6)
I believe the answer is:
irking
'bothering' is the definition.
(I've seen this in another clue)
'single romeo with card' is the wordplay.
'single' becomes 'I' (one).
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'with' is a charade indicator (letters next to each other).
'card' becomes 'king' (type of playing card).
'i'+'r'+'king'='IRKING'
(Other definitions for irking that I've seen before include "Irritating, vexing" , "Annoying, bothering" , "Annoying, irritating" , "Disgusting" .)