Expert fancies ignoring the odds (3)
I believe the answer is:
ace
'expert' is the definition.
(ace is a kind of expert)
'fancies ignoring the odds' is the wordplay.
'ignoring the odds' indicates alternate letters (letters in odd-numbered positions are removed).
The alternate letters of 'fancies' are 'ACE'.
(Other definitions for ace that I've seen before include "reason for point of no return" , "Player who excels" , "Single unit on playing cards" , "rare driving result?" , "Playing card with single spot" .)