The story
- Proto-Indo-European*per-
- Proto-Italic*peri-
- Latinper-
- Proto-Indo-European*(s)peys-der.?
- Latinspīrō
- Latinperspīrō
- Latinperspīrābilis
- English todayperspirable
Borrowed from Latin perspīrābilis. By surface analysis, perspire + -able.
Etymology from Wiktionary, CC BY-SA 4.0.