Noted his job is on the slide (10)
I believe the answer is:
trombonist
'noted his job' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'is on the slide' is the wordplay.
I cannot quite understand how this works, but
'is' is found in the answer.
'on' is found in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
This explanation may well be incorrect...
(Other definitions for trombonist that I've seen before include "Ted Heath, perhaps" , "Brass player" .)