Green’s Dictionary of Slang

marish and parish phr.

[SE marish, a marsh + parish, a local governmental sub-division. Allsopp, Dict. Caribbean English Usage (1996), presumes some lost UK dial. phr. transported to W.I.]

(W.I., Bdos/Guyn./Trin.) everyone.

[WI]F. Collymore Notes for Gloss. of Barbadian Dial. 74: Marish and the parish will be there: i.e., everybody.