slang To vomit (something). A noun or pronoun can be used between "yak" and "up." The dog has this nasty habit of eating candles off the table and then yakking them up all over the carpet later. We both yakked up our dinner the whole night, so there was definitely something wrong with what they served us.
yak upor yack up
To eject some contents of the stomach by vomiting: He was so sick today that he yakked up his lunch. The dog ate some leather and then yakked it up.
yak it up
tv. to talk incessantly or a lot. Why don’t you all just yak it up while I get ready to give the talk?