D defs.my
Entry 6 senses Webster, 1913

Obsession

/əb-sĕsh'-ən/ · Ob·ses·sion · IPA /əbˈsɛʃən/
01 n. The act of besieging.
  1. 1.
    The act of besieging.[archaic]
  2. 2.
    The state of being besieged; -- used specifically of a person beset by a spirit from without.[archaic]
    “Whether by obsession or possession, I will not determine.” — Burton.
  3. 3.
    An excessive preoccupation of the thoughts or feelings; the persistent haunting or domination of the mind by a particular desire, idea, or image.
  4. 4.
    Any driving motive; a compelling goal; -- not necessarily implying a negative judgment, as does sense 3; as, the coach was obsessed with winning the state championship
  5. 5.
    Something that causes an obsession{3}.
  6. 6.
    The state of being obsessed.