The only job for which a person is absent (3-3)
I believe the answer is:
one-off
'the only job for' is the definition.
The definition suggests a singular noun which matches the answer.
'a person is absent' is the wordplay.
'a person' becomes 'one' (**).
'is absent' becomes 'off' (I've seen this in other clues).
'one'+'off'='ONE-OFF'
'which' acts as a link.
Can you help me to learn more?
(Other definitions for one-off that I've seen before include "A single event, not reproduced or repeated" , "Unrepeatable experience" , "Item made once only" , "Not repeated, being a single event or object" , "Not repeated or reproduced, a single thing" .)