Means of gauging a boring job (7)
I believe the answer is:
calibre
'job' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for calibre that I've seen before include "Ability; barrel diameter" , "Diameter of a gun barrel" , "weapon's bore?" , "Level of ability; bore" , "measure of a bore" .)