mid-15c., perhaps a shortening of Old French pantaisier "gasp, puff, pant, be out of breath, be in distress" (12c.), probably from Vulgar Latin *pantasiare "be oppressed with a nightmare, struggle for breathing during a nightmare," literally "to have visions," from Greek phantasioun "have or form images, subject to hallucinations," from phantasia "appearance, image, fantasy" (see phantasm). Related: Panted; panting.
"a gasping breath," c.1500, from pant (v.).
v. pant·ed, pant·ing, pants
To breathe rapidly and shallowly.