Unknown’s withdrawn from Irish part in series that comes to nought? (9)
I believe the answer is:
countdown
'part in series that comes to nought?' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'unknown's withdrawn from irish' is the wordplay.
I cannot quite see how this works, but
'from' could be 'un' (I've seen this in other clues) and 'un' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for countdown that I've seen before include "It ends 2, 1, zero" , "Pre-launch procedure" , "TV quiz show" , "The reckoning" , "Numeric process immediately prior to launching spacecraft" .)