obsessed

The word "obsessed" originates from the Latin verb obsidēre, meaning "to besiege," which is a compound of ob- ("against") and sedēre ("to sit"). The literal image is of an army sitting down against a fortress, blockading it completely. In the 16th century, the term was adopted into English in its past participle form to describe a state of being mentally besieged or haunted by a fixed idea, as if one's mind were occupied by a persistent force. This evolved into the modern psychological sense of having one's thoughts completely and excessively preoccupied by a specific subject or person.

Structure: ob + sess + ed - ob (Latin origin): A prefix meaning "against," "toward," or "completely." - sess (Latin origin): From the root of the verb sedere, meaning "to sit." - ed (English origin): A suffix forming the past participle of verbs, here used to create an adjective.