mid-13c., "animating or vital principle in man and animals," from Old French espirit, from Latin spiritus "soul, courage, vigor, breath," related to spirare "to breathe," from PIE *(s)peis- "to blow" (cf. Old Church Slavonic pisto "to play on the flute").
Original usage in English mainly from passages in Vulgate, where the Latin word translates Greek pneuma and Hebrew ruah. Distinction between "soul" and "spirit" (as "seat of emotions") became current in Christian terminology (e.g. Greek psykhe vs. pneuma, Latin anima vs. spiritus) but "is without significance for earlier periods" [Buck]. Latin spiritus, usually in classical Latin "breath," replaces animus in the sense "spirit" in the imperial period and appears in Christian writings as the usual equivalent of Greek pneuma.
Meaning "supernatural being" is attested from c.1300 (see ghost); that of "essential principle of something" (in a non-theological sense, e.g. Spirit of St. Louis) is attested from 1690, common after 1800. Plural form spirits "volatile substance" is an alchemical idea, first attested 1610; sense narrowed to "strong alcoholic liquor" by 1670s. This also is the sense in spirit level (1768).