What is the meaning of Mump?

To mumble, speak unclearly.

To move the lips with the mouth closed; to mumble, as in sulkiness.

To beg, especially if using a repeated phrase.

To deprive of (something) by cheating; to impose upon.

To cheat; to deceive; to play the beggar.

To be sullen or sulky.

To nibble.

(Of a police officer) to accept a small gift or bribe in exchange for services.

A grimace.

A cube of peat; a spade's depth of digging turf.

Source: wiktionary.org