Translates literally as "no problem" but interpreted in English as "relax" or "take it easy" (also written Momentai)
Its a Cantonese phrase made famous by the Bandai show Digimon Tamers, by the Digimon character Terriermon, who it has almost become a trademark phrase.
It's really written Momantai or Moumantai, but stupid monolingual Anglos with no hearing that speak with a potato in their mouth will keep writing "Momentai all over the internet.
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)