A sound said or written in the start of an sentence(most times anyway), to express something related to 'negative' things, or as a no.
Also used as an evil laugh, short for mwahaha.
#1
Person: Hi, wanna go buy some cake?
Other person: Mwah, i'm broke.
#2
Person: *falls down the stairs*
Other person: Mwah! xD
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