spir

The root spir comes from Latin spīrāre, "to breathe." To the Romans, breath was not just air moving in and out of the lungs — it was the visible sign of life itself. The closely related noun spīritus meant "breath," but because breathing is what separates the living from the dead, it slid naturally into "the breath of life," then "soul," and finally "spirit." This double life — physical breathing on one side, life-force and soul on the other — is the key to the whole family.

Once you hold that image of breathing in your head, the prefixes do all the work:

- in- (in) + spirare → inspire: literally "to breathe into." The ancients imagined a god breathing an idea straight into a poet's chest. Today it just means to fill someone with energy or ideas — but the picture is the same: something is breathed into you.
- ex- (out) + spirare → expire: "to breathe out." Your last act in life is to breathe out one final time, so expire came to mean "to die," and from there "to come to an end" — a contract or passport breathes its last and expires.
- a-/ad- (toward) + spirare → aspire: "to breathe toward" something. Picture someone panting with the effort of reaching upward — to aspire is to strain toward a goal you badly want.
- con- (together) + spirare → conspire: "to breathe together." Picture two people with their heads close, whispering — so close they share the same breath. That huddle of shared breath is exactly the image of a plot.
- re- (again) + spirare → respire: "to breathe again and again." This stayed literal: respiration is the in-and-out of breathing, and respiratory describes the lungs and airways that do it.
- per- (through) + spirare → perspire: "to breathe through" — through the skin. The word pictures sweat as the skin quietly breathing, so perspire became the polite word for sweating.
- trans- (across) + spirare → transpire: "to breathe across / give off vapour." Plants transpire by releasing water vapour. By a strange leap, "vapour leaking out" became "information leaking out" → "to become known," and then loosely "to happen."
- dis- (away) + spirit → dispirit: to take the spirit (breath of life) away from someone, leaving them deflated and discouraged.

The whole family is unusually pure — almost every member traces straight back to spīrāre with no surprise outsiders. Just remember the two faces of breath: the literal lungs (respire, perspire, expire) and the metaphor of breath-as-life-and-soul (spirit, inspire, conspire, aspire). The prefix always tells you the direction the breathing goes: into, out of, toward, together, again, through, across, away.