mar verb
1 to kill; to hurt or punish, to strike: Mar the gaugie wi a clemmie, clach, or bar. [Fell the man wi a stone.] la19-.
2 to fight: We don't get hit at home. Granny says the men can pummel their fists and mar with each other all they like ... 20-.
3 to break 20-. etymology: Romany; possibly derived from Hindi mārna ‘to strike’; or simply a Scots contraction of murder as brar is for brother; sense 2 attested by Galloway and Perthshire and Argyleshire Tinkler-Gypsies; senses 1 and 2 attested by ET; sense 1 collected by Simson (1865) and by Joseph F G S Lucas and Rev John Baird from Kirk Yetholm Gypsies and attested by SS; sense 3 attested by BS in TDITA note:

Smart & Crofton (1875) collected the form maur ‘to kill’ from English Gypsies.

Canadian Paul Pope (2013) cites mar ‘to break; to fight; clout, hit’ and also cites marred ‘broken’.