Spirits are alcohol that is generally about 40% alcohol.
They are produced by first fermenting something to produce the alcohol, then distilling the alcohol to concentrate the alcohol content. Spirits can’t be produced by fermentation alone, because fermentation can only get up to a maximum of 16 or 17 % alcohol.
The word “spirits” is generally used by people in the alcohol trade to mean good quality alcohol, with the word liquor applied to equally-strong alcohol that they would call “rotgut.” However, this doesn’t stop others such as scientists and those in industry from applying it to all strong, distilled alcohol, whether or not it is even safe for human consumption. Neutral grain spirit in fact is usually classed as a spirit.
Spirits are very inflammable.