Green’s Dictionary of Slang

mard-arse n.

[dial. mardy, sulky, in turn f. dial. mar, to spoil or over-indulge a child + arse, used as general pej. rather than actual physical description]

a sulky person.

Show quotations
F. Kitchen Brother to the Ox n.p.: He threatened to ‘screw my neck round if I didn’t let the wench a be,’ and called me a ‘mardarse’.
[UK]B. Naughton ‘Late Night on Watling Street’ in Late Night on Watling Street (1969) 3: Right enough it was that damn great mardarse, Babyface.
[UK](con. 1950) J. Rosenthal Spend, Spend, Spend Scene 9: All right, mard-arse! Where’s she hidden them?