M

[manky]  {adj.}

dirty, filthy. (Polari).

[marbles]  {n.}

Wits. As in, to lose one's marbles.

[mare]  {n.}

Woman (derogatory).

[mark]  {n.}

A suitable victim for a con or swindle.

[matelot]  {n.}

Sailor (from the French).

[meat and two veg]  {n.}

Literally a traditional meal consisting of any meat, potatoes and a second type of vegetable; euphemistically the male external genitalia. Is sometimes also used to mean something unremarkable or ordinary.

[mental]  {adj.}

Crazy or insane.

[Mick]  {n.}

An Irishman (derogatory).

[miffed]  {adj.}

Upset or offended.

[milk run]  {n.}

A 'safe' mission or patrol.