quell

Where it comes from

Quell now means to put an end to something, often by force: police may quell a riot, or reassurance may quell a fear. Old English cwellan meant to kill or cause to die, and Middle English quell retained the forceful sense of killing or destroying. Over time, the usual meaning weakened from destroying a person or creature to suppressing an action, feeling, or disturbance. That history explains the word’s pressure. You can calm a worried child gently, but quell suggests overcoming resistance or stopping something that threatens to continue.

How the meaning developed

Quell no longer ordinarily means kill, but its old severity still makes it a forceful way to say suppress completely.

In use

Instead of “Calm this down.”
Try “Kindly quell the commotion.”

To “quell” is to suppress something completely or make it cease. “Commotion” means noisy disturbance.
“Kindly” makes the forceful request sound absurdly polite.