He has a trying job (5)
I believe the answer is:
judge
'he has a trying job' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'jud' and 'jud' is found in the answer.
The remaining letters 'ge' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for judge that I've seen before include "rule" , "Estimate" , "Form an opinion of" , "Arbitrator" , "Senior officer of the law" .)