6 letters · 8 points in Scrabble
verb haunt like a ghost; pursue
verb be preoccupied with something
originFrom Latin obsessus, perfect passive participle of obsideō (“sit on or in, remain, besiege”), from ob- (“before”) + sedeō (“to sit”); see sit, session, etc.; compare assess, possess.
Etymology from Wiktionary, CC BY-SA 3.0