Obsession

n.	1.	The act of besieging.
	2.	The state of being besieged; - used specifically of a person beset by a spirit from without. Whether by obsession or possession, I will not determine. - Burton.
	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.	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.	Something that causes an obsession{3}.
	6.	The state of being obsessed.

Noun	1.	obsession - an irrational motive for performing trivial or repetitive actions against your will Synonyms: compulsion
	2.	obsession - an unhealthy and compulsive preoccupation with something or someone Synonyms: fixation

absorbed attention, absorption, abstraction, abulia, alienation, anxiety, anxiety equivalent, anxiety state, apathy, application, bedevilment, bewitchery, bewitchment, captivation, catatonic stupor, complex, concentration, contemplation, conviction, deep study, deep thought, dejection, depression, detachment, elation, emotionalism, enchantment, engagement, engrossment, entrancement, euphoria, fascination, fixation, fixed idea, folie du doute, hang-up, hypercathexis, hypochondria, hysteria, hysterics, idee fixe, illusion, immersion, indifference, insensibility, intentness, involvement, irresistible impulse, lethargy, maya, meditation, melancholia, mental distress, monomania, morbid drive, obsessive compulsion, pathological indecisiveness, phobia, possession, prepossession, profound thought, psychalgia, psychomotor disturbance, rapt attention, ruling passion, single-mindedness, spirit control, studiousness, study, stupor, submersion, thing, tic, twitching, unresponsiveness, witchery, withdrawal