get tired of, get sick of something

きる(あきる) To get tired of something you used to like: I’m bored of this video game, let’s try another one.
 
うんざり (Angrier than 飽きる) To get fed up with something you never liked in the first place:paperwork, being scolded. You can say this to someone’s face if they’re bothering you.
 
へきえき (the rudest) utterly fed up! Unlike うんざり, へきえき is anecdotal: you wouldn’t say it to the person’s face, but you’d say it to your friend while telling the story later. Also you only use うんざり and へきえき about things or situations that you can’t quit – where you have to do it or you have to deal with that person.