Meaning

originRepresenting no pronounced with the mouth snapped closed at the end. Luick instead claims it represents a realisation of no with final [ʔ], with a purported reduction of /p/ to [ʔ] in before syllabic liquids providing a model for the spelling of [ʔ] as -pe, but it is more parsimonious to assume that the -pe directly represents attested realisations with [p̚]. Compare yep, welp, ope, and yup.

Etymology from Wiktionary, CC BY-SA 3.0