preoccupy vs obsess

preoccupy and obsess both are verbs.

Word	Noun	Adjective	Verb	Adverb
preoccupy	No	No	Yes	No
obsess	No	No	Yes	No

As verbs, obsess is a hyponym of preoccupy; that is, obsess is a word with a more specific, narrower meaning than preoccupy:

preoccupy: engage or engross the interest or attention of beforehand or occupy urgently or obsessively
obsess: haunt like a ghost; pursue

Other hyponyms of preoccupy include ghost, haunt, prepossess.

preoccupy (verb)	obsess (verb)
engage or engross the interest or attention of beforehand or occupy urgently or obsessively	haunt like a ghost; pursue
occupy or take possession of beforehand or before another or appropriate for use in advance	be preoccupied with something