Top club, perhaps on island (5)

I believe the answer is:
cardi
'top' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'club perhaps on island' is the wordplay.
'club perhaps' becomes 'card' (clubs is a playing card suit).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'island' becomes 'i' (geographical abbreviation).
'card'+'i'='CARDI'
Can you help me to learn more?
(Another definition for cardi that I've seen is " woolly".)
