I've taken this from my own website. Here is a list of words that are being used by ancafe and their fans. Correct me if I’m wrong.

Nyappy: ‘Happy’. Nyappy comes from the word ‘happy’, they have been using it for a long time by now. Unnyappy is the opposite of nyappy. (Unhappy) Nyappy can also be a greeting to someone else like; ‘hello’. Mostly being used by ancafe and their fans to communicate.

Tiramisu: ‘Have a good day’. It’s also an Italian dessert, but ancafe use it as ‘have a good day’.

Poppoo: ‘Poppoo’ comes from ‘hato’ (translates to ‘dove’), which is a symbol of peace and ‘poppoo’ is the sound a dove makes. (Credits to: JaME world)

Cafekko: This is how the band call their fans. ‘cafe’ comes from their band name and ‘ko’ means ‘child’.