handwave
handwave
If someone starts a sentence with "Clearly..." or"Obviously..." or "It is self-evident that...", it is a goodbet he is about to handwave (alternatively, use of theseconstructions in a sarcastic tone before a paraphrase ofsomeone else's argument suggests that it is a handwave). Thetheory behind this term is that if you wave your hands at theright moment, the listener may be sufficiently distracted tonot notice that what you have said is wrong. Failing that, ifa listener does object, you might try to dismiss the objectionwith a wave of your hand.
The use of this word is often accompanied by gestures: bothhands up, palms forward, swinging the hands in a verticalplane pivoting at the elbows and/or shoulders (depending onthe magnitude of the handwave); alternatively, holding theforearms in one position while rotating the hands at the wristto make them flutter. In context, the gestures alone cansuffice as a remark; if a speaker makes an outrageouslyunsupported assumption, you might simply wave your hands inthis way, as an accusation, far more eloquent than words couldexpress, that his logic is faulty.