preoccupancy vs state of mind

preoccupancy and state of mind both are nouns.

Word	Noun	Adjective	Verb	Adverb
preoccupancy	Yes	No	No	No
state of mind	Yes	No	No	No

As nouns, state of mind is a hypernym of preoccupancy; that is, state of mind is a word with a broader meaning than preoccupancy:

Other hypernyms of preoccupancy include cognitive state.

preoccupancy (noun)	state of mind (noun)
the act of taking occupancy before someone else does	the state of a person's cognitive processes
the mental state of being preoccupied by something	a temporary psychological state