“Mardy, mardy mustard your feet are made of custard.”
playground insult/chant -Derbyshire
Mardy is a mainly Midland word (Staffordhsire/Nottinghamshire/Derbyshire). Some people think that it comes from the word mard, meaning spoilt which itself comes from the Standard English word mar (to mar something) a likely derivation being marred (+ y), pronunciation ‘ma:di’.
Mardy (comparative mardier, superlative mardiest) means: awkward; uncooperative; bad-tempered or terse in communication; whiny; aloof; stroppy, moody, miserable or sulking like a small child. The mardies is a fit of petulance.
Frequently combined with other words forming common phrases such as “mardy bum”, “mardy mustard” or “mardy custard” and “mardy bugger”. Sometimes shortened to “mard” particular when used in certain phrases such as “mard arse”, “in a mard” or “mard on” (as in “he’s got a mard on” to mean he’s in a bad mood).
D. H. Lawrence 1913 in Sons and Lovers, chapter 2 “I wouldn’t be such a mardy baby,” said his wife shortly. In 1984 Food, Health, and Identity, Patricia Caplan [1997 edition] “When our Jonathan’s poorly… he’s mardy, very mardy.”