Fast mail used for one's resignation (8)
I believe the answer is:
fatalism
'one's resignation' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'fast mail used' is the wordplay.
'used' indicates an anagram.
'fast'+'mail'='fastmail'
'fastmail' anagrammed gives 'FATALISM'.
'for' is the link.
Can you help me to learn more?
(Other definitions for fatalism that I've seen before include "Doctrine that says humans have no control over events" , "Belief that events are predetermined" , "Doctrine that all events are subject to fate, and happen by unavoidable necessity" , "Acceptance of events" , "Acceptance of whatever happens as inevitable" .)