Unusual to get second chances (4)
I believe the answer is:
odds
'chances' is the definition.
(the odds of something happening)
'unusual to get second' is the wordplay.
'unusual' becomes 'odd' (similar in meaning).
'to get second' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'odd'+'s'='ODDS'
Can you help me to learn more?
(Other definitions for odds that I've seen before include "Scraps" , "Likelihood of something happening" , "Betting rates" , "Ratios set by bookies" , "(In betting) chances" .)