preoccupation vs thought

preoccupation and thought both are nouns.

Word	Noun	Adjective	Verb	Adverb
preoccupation	Yes	No	No	No
thought	Yes	No	No	No

As nouns, thought is a hypernym of preoccupation; that is, thought is a word with a broader meaning than preoccupation:

Other hypernyms of preoccupation include idea.

preoccupation (noun)	thought (noun)
the act of taking occupancy before someone else does	the process of using your mind to consider something carefully
the mental state of being preoccupied by something	the content of cognition; the main thing you are thinking about
an idea that preoccupies the mind and holds the attention	the organized beliefs of a period or group or individual
	a personal belief or judgment that is not founded on proof or certainty