The Latin verb spirare, meaning “breathe,” is the source of a number of verbs (and other parts of speech). Here’s a summary of these words and their meanings.
Aspire literally means “breathe on”; the connotation is that one breathes heavily with the exertion of aspiring to a goal. The modern sense of aspire is “try to be or do something,” and the noun form aspirant refers to someone who is a candidate or contestant.
To conspire (the word literally means “breath together”) is to plot, or plan a scheme with others. Plotters are also called conspirators, and conspiracy is a synonym for plot.
Expire means “breathe out” but usually connotes the end of an offer or of a product’s shelf life; the noun form is expiration. (In Latin, expirare also meant “die,” and this sense carried over into English, although it is now rare.) The literal meaning of inspire is “breathe in”; the figurative sense derived from the idea that a deity breathes life into a mortal. The verb and the noun now chiefly pertain to that sense—of having an emotion or a feeling that prompts one to create or to cause something to happen. (An inspiration can also be someone or something that has a role in the accomplishment of a creative act or an event.)
Perspire, meaning “breathe through,” is associated with the production of sweat; the noun form is perspiration. The verb respire (literally, “breathe again”) is rare, but the noun form respiration, which refers to the breathing cycle of inhaling oxygen into the body and exhaling carbon dioxide, is common. Suspire (literally, “breathe under”) is a rare synonym for sigh. Transpire, which literally means “breathe (or evaporate) across,” refers to evaporation of water from leaves (a process called transpiration) but has, by extension, come to mean “become known” as well as “happen” or “occur,” now the predominant senses of the word.
Two technical terms derived from the Latin root are spirant, a linguistic term for a breathy consonant, and spirometer, the name of a device for measuring lung capacity; the principle is called spirometry.
Finally, a related term is spirit. The word has multiple meanings: It became associated with divine power (see the reference to the figurative sense of inspire above) and, by extension, came to pertain to one’s character or nature, or the essential principle of something, and to denote courage, enthusiasm, or vigor. (Also based on the supernatural sense, it serves as a synonym for ghost.) In addition, it acquired in alchemy an association with volatile substances and ultimately came to be applied to alcoholic beverages.
(Spire, referring to a tapering element such as the pinnacle of a tower, comes from an unrelated word for a sharp point; spear, however, is cognate with spire. Spiral, likewise, is unrelated both to the -spire family of words and to spire and spear.)