An term used to insult and describe a really ugly looking person, comes from the blending of the lexemes "beast" and "yeti" and means UGLY! or DOG!
Can be used as a noun or as an adjective.
Person 1: "hey! check out that person over there"
Person 2: "oh man... YEAST!!!"
Person 1: "ey bro did ya see that chick i was danc'in wif in da club?"
Person 2: "fuk bro.. she was yeast"
*ugly person walks past*