What's the difference between mumper and pumper?

Mumper

Definition:

• (n.) A beggar; a begging impostor.

Example Sentences:

Pumper

Definition:

• (n.) One who pumps; the instrument or machine used in pumping.

Example Sentences:

• (1) Similar patterns of mortality were seen, although there was a significant excess of thyroid cancer in those employed as pumper-gaugers.