moenie
/ˈmʊni/(also moeni, mooni) informal
verb
[no object] And as an auxiliary with bare infinitive: don't; (you) mustn't. Frequently used humorously in phrase moenie panic (also worry) (nie): don't panic, don't worry.
Origin
Early 20th century; earliest use found in Charles Pettman (b. 1851). From Afrikaans moenie —— (nie) must not, do not ——, shortened from Dutch moet niet from moet + niet.