None of the printed lines shows this as a piece of Korean grammar. Every one of them is the syllable sitting inside a borrowed English word — 'moment', 'woman', the snack brand Munch — or a game in which somebody is reading the letters M-O-N aloud. There is nothing here to define, so no meaning is claimed. If you heard this in a video, it was most likely part of an English loanword rather than a grammatical ending.
The examples below did not fully pin this one down — read them before relying on the entry above.