Ace dismissed by harassed course trainer, being late riser? (12)
I believe the answer is:
resurrection
'ace' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's an association between them I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for resurrection that I've seen before include "Act of restoring to life" , "A rising from the dead" , "Revival" , "Christ's rising after his crucifixion" , "Act of coming back to life after death" .)