obsess vs preoccupy

obsess and preoccupy both are verbs.

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

As verbs, preoccupy is a hypernym of obsess; that is, preoccupy is a word with a broader meaning than obsess:

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

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