From m- + English stingy.
mstinji (m-wa class, no plural)
- (Sheng) miser, stingy person
- Synonym: mbahili
2023 January 4, Alexander Nderitu, “Kenyans Get a Taste of “The French Shakespeare””, in The Theatre Times[1] (in English):‘Mstinji’ is Kenyan urban slang for ‘stingy’ people, Uncle Scrooge-type characters.