Definition & Meaning of "mardy"in English

What does "mardy" mean in British slang?

The structure is a simple adjective of uncertain origin, possibly from the dialectal "mard" (to spoil or pamper), influenced by "marred" (spoiled). It is used in British English, particularly in Northern England and the Midlands (especially Yorkshire, Derbyshire, and Nottinghamshire), to mean moody, sulky, easily upset, or in a bad mood, often in a childish or exaggerated way. People typically say "Don't get mardy" or "She's been mardy all day."