Cancel eccentric form of lottery (11)
I believe the answer is:
scratchcard
'form of lottery' is the definition.
(I've seen this before)
'cancel eccentric' is the wordplay.
'cancel' becomes 'scratch' (I've seen this before).
'eccentric' becomes 'card' (card can mean an eccentric person).
'scratch'+'card'='SCRATCHCARD'
(Other definitions for scratchcard that I've seen before include "Gambler's investment rubbed with a coin" , "Rubbed lottery ticket" , "Ticket for instant lottery" , "form of lottery" .)