Not even second chances (4)
I believe the answer is:
odds
'chances' is the definition.
(thesaurus)
'not even second' is the wordplay.
'even' means one should take alternating letters (even-numbered letters are used).
'second' becomes 'dds' (I can't justify this - if you can you should give a lot more credence to this answer).
The alternating letters of 'not' are 'o'.
'o'+'dds'='ODDS'
Can you help me to learn more?
(Other definitions for odds that I've seen before include "They could be evens" , "Starting price" , "Betting ratio" , "Things not even" , "(In betting) chances" .)