Someone who generally acts like an idiot or sleezebag and adorns his/her self with overly tacky clothing, jewelry, and/or electronic devices. Said person is usually arrogant and cares little about those perceived to be "beneath" him/her.
Jane: Did you see that tacky couple at the cafe yesterday sucking face and yelling at the servers in front of all those kids?
Sally: Yeah, I sure did. What a couple of bouchies!