Still small chances (5)
I believe the answer is:
evens
'chances' is the definition.
(I've seen this before)
'still small' is the wordplay.
'still' becomes 'even' (synonyms).
'small' becomes 's' (abbreviation - e.g. clothes size).
'even'+'s'='EVENS'
(Other definitions for evens that I've seen before include "Kind of betting odds on seven" , "Chances" , "50-50 chance" , "Quits" , "Kind of bet where odds are one to one" .)