"Now if you will excuse me, I have a most onerous duty to perform."

Considering the health and safety of those who do this work should not be an onerous duty.

I do know they dearly wanted to be relieved of this most onerous duty.

Satisfied that Roanna was being taken care of, he couldn't put off his onerous duty any longer.

"Taking some time off, is he, from his onerous duties on the Hill?"

Cleveland's income with the firm was not high, but neither were his duties especially onerous.

We have enough men now so that we can rotate them for the most onerous duty.

He but does his duty - an onerous duty, it seems to me.

Care must be taken to ensure the Firm does not take a more onerous duties than are required of it.

It is my onerous duty to report to you!