Not accept one’s to break into time off (6)
I believe the answer is:
resist
'not accept' is the definition.
I can't tell whether this definition defines the answer.
'one's to break into time off' is the wordplay.
'one's' becomes 'i's' (Roman numeral).
'to break into' indicates putting letters inside (inserted letters break into the word).
'time off' becomes 'rest' (I've seen this in another clue).
'is' placed within 'rest' is 'RESIST'.
Can you help me to learn more?
(Other definitions for resist that I've seen before include "Oppose or fight against someone" , "Withstand a force" , "Defy for sister" , "Withstand, oppose" , "Check; withstand" .)