disputant

As it was useless arguing with so pertinacious a disputant we were compelled humbly to submit.

"After all, I only asked to work and to be at peace," he said aloud, as if in answer to some insistent disputant.

In conversation he was a singularly eager, acute and pertinacious disputant.

I must, however, allow that Mr. Henson is a courteous disputant, and I hope I shall reciprocate his good feeling.