demonstrate

To demonstrate something is to show it plainly enough that nobody has to take your word for it. A shop assistant demonstrating how the blender locks into its base, a teacher demonstrating a knot with a length of rope.

From there it stretches to proof: the figures demonstrate that the scheme is working, the study demonstrates a clear link. It also covers what people show by acting — she demonstrated real patience, he demonstrated no interest at all. Then there is the street sense: thousands demonstrated outside the embassy, which is protest, not proof. The noun demonstration carries both loads, a demonstration of the machine and a demonstration against the war, with demo as the short form. Demonstrable and demonstrably mean it can be proved; demonstrative means showing your feelings openly — and in grammar the demonstratives are this, that, these and those.