obsess
1. [ verb ] haunt like a ghost; pursue
Synonyms: haunt ghost
Examples:

"Fear of illness haunts her"

Related terms: preoccupy preoccupy ghost
2. [ verb ] be preoccupied with something
Examples:

"She is obsessing over her weight"

Related terms: worry obsession
Similar spelling:   obsessed
  obsessive
  obsession
  object