Odds, oddly, may be this! (5)
I believe the answer is:
evens
'odds' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for evens that I've seen before include "Odds on something very likely to win" , "Level odds?" , "Chances" , "1-1" , "Kind of betting odds on seven" .)