1 native, local, regional, indigenous, autochthonous:
Old Hebrew fell out of use, to be replaced by vernacular Aramaic.
2 popular, informal, colloquial, conversational, ordinary, familiar, everyday, spoken, vulgar, vulgate; plain, simple, straightforward, easy:
We have both the vernacular and the formal, literary, or clerical levels of language. Can you translate this scientific gobbledegook into vernacular English that we can understand?
3 jargon, patois, argot, cant, idiom, phraseology, language, talk, speech:
Alf occasionally slips into the vernacular of a Billingsgate fishmonger (his former calling ) .