Etymologically, the English word spirit has its roots in ancient language the people who spoke these words were not using them metaphorically , but as the meaning intended literally.
Spirit (from latin spiritus/spirare literally breath, of the wind, breathe or blow)was not used when spoken as metaphorical but as the understood definitions.
Similarly the words : pneuma(greek) as in pneumatic, pneumonia .Lil (sumarian)air, breath would be translated as spirit.
Ruakh( aramaic/ hebrew )lliterally breath, air that is breathed also wind, force of wind/air .
Nephesh/neshamah( hebrew) literally breath.
The supernatural meanings of spirit are not the etymological roots, these later interpretations (understandable in less enlightened times)were a hijacking of the literal meanings to suit supernatural belief systems. Eg..the writer (whoever )of genesis chooses to describe god giving adam air( ruakh) in his nostrils to give him life. God the giver is supernatural , adam the receiver is myth the air however (ruakh) is literal chosen (hijacked) later to be seen also as ' supernatural '.as alluded to by the opinion of the dutch site Positief-atheism,...that "the original words acquired mystical status by believers".
Also in Edward R Bevans book 'symbolism and belief' that the view stated by Siebeck and also Cremer in his lexicon of biblical greek, states that the word pneuma(spirit in English)did not get a spiritual(supernatural) connotation till it was adopted by jews to translate the Aramaic/hebrew ruakh.
The fact that ancients believed in supernatural superstition in whatever form as mentioned previously in the topic ie Pythia greek mythology, Etemuu ghost stories , Anaximenes ancient philosopher who saw the correlation of spirit and air , but chose to believe it had ' devine attributes, does not detract from the root meaning of spirit and corresponding words in other languages and etymology of those being that it was literally : air we breathe, wind , force of wind, breath, blow also ' of the wind '.
These words therefore not always metaphorical (although certainly can be used as such) but used and spoken by ancients in their literal meaning/context.
Therefore I would conclude that spirit is exactly a word which can be defined as supernatural form(total non...sense imo)
Spirit is also exactly a word which is descriptive of human traits, behavior, attitudes etc, but can also be applied to animals eg a 'spirited horse' meaning excited, agitated.
Spirit is exactly a word derived etymologicaly from root and very ancient origins to be no more than the air we breath literally.
Best wishes