Haunt is a verb that means to disturb or occupy one's mind compulsively or persistently. There are many other words that can be used instead of haunt that convey similar meanings. For instance, the word "torment" can be used to describe a persistent and irritating thought or memory that keeps returning. The word "plague" means to trouble or annoy someone persistently, while "bedevil" means to cause constant irritation, confusion or distress. "Obsess" is another word that can be used to describe a persistent and haunting thought or idea. Other possible synonyms for haunt are harass, pester, trouble, agitate, and disturb.