means To breathe with a rough, whistling sound, usually because the airways are narrowed or congested; also, informally, a clever scheme or old joke.

from From Old English or Old Norse roots — likely the Old Norse 'hvæsa,' meaning to hiss, a fittingly breathy ancestor. The word itself is essentially onomatopoeic: it sounds like the labored rasp it names. The 'clever scheme' sense is a later British slang development, probably from the idea of a theatrical performer's improvised, well-worn gag — a comic bit 'wheezed out' on cue.