Mchew/ mtchew is something that is used in Nigeria a lot and you use it when you are frustrated with someone or something or someone is annoying you.
You such your teeth and make a sound.
when someone says something so unreasonably foolish and stupid theres no way to reply to the statement they have just said so you smack your lips making a 'mtchew' noise. it is also used to express annoyance, disappointment or some cases used to show in a friendly way distaste for a sarcastic remark. it is sort of a 'ugh' for black people or used as a eye roll but as a word. the word is when your tongue is sucking your teeth/
a person w h o m you think is gay. like you have a certain vibe from them, but you have no proof to back it up because everything they say is gay but they say, " no homo"