Late Middle English (in the sense 'emit as vapour through the surface'): from French transpirer or medieval Latin transpirare, from Latin trans- 'through' + spirare 'breathe'. Sense 1 (mid 18th century) is a figurative use comparable with ‘leak out’.

• spirit from Middle English:

  Our word spirit is based on Latin spiritus ‘breath or spirit’, from spirare ‘to breathe’—the ancient Romans believed that the human soul had been ‘breathed’ into the body—the image is the same as ‘the breath of life’. The sense ‘strong distilled alcoholic drink’ comes from the use in alchemy of spirit to mean ‘a liquid essence extracted from some substance’. People sometimes say the spirit is willing but the flesh is weak when they have good intentions but yield to temptation and fail to live up to them. The source is the New Testament, where Jesus uses the phrase after finding his disciples asleep in the Garden of Gethsemane despite telling them that they should stay awake. Spirare forms the basis of numerous English words including aspire (mid 16th century) from adspirare ‘to breath upon, seek to reach’; conspire (Late Middle English) from conspirare ‘to breath together, agree’; expire (late 16th century) ‘to breath out’; inspire (Late Middle English) ‘breath into’ from the idea that a divine or outside power has inspired you; and perspire (mid 17th century) ‘to breath through’; and transpire (Late Middle English) ‘breath across. In English spirit was shortened to sprite (Middle English) which in turn developed sprightly (late 16th century).