Definition of plough jag in US English:

plough jag

(US plow jag)

noun

English Regional, Lincolnshire
  • A mummer participating in the celebration of Plough Monday.

Origin

Mid 19th century. Apparently alteration of plough jack (although this is first attested slightly later).

Pronunciation

plough jag

/ˈplaʊ dʒaɡ/