A short nose that becomes longer when he is under stress (chapter 3), especially while lying. In the original tale, Collodi describes him as a "rascal," . 

Pinocchio's bad behavior, rather than being charming or endearing, is meant to serve as a warning. Collodi originally intended the story, which was first published in 1881, to be a tragedy. It concluded with the puppet’s execution. Pinocchio’s enemies, the Fox and the Cat, bind his arms, pass a noose around his throat, and hang him from the branch of an oak tree.

The nose appears only a couple of times in the story, but it reveals the Blue Fairy's power over Pinocchio when he acts disobediently. After struggling and weeping over his deformed nose, the Blue Fairy summons woodpeckers to peck it back to normal. 

Pinocchio is a wooden  marionette(a puppet that is manipulated with wires) and not a hand puppet(directly controlled from inside by the puppeteer's hand). But the piece of wood from which he is derived is animated, and so Pinocchio moves independently. Basically good, he often gets carried away by bad company and is prone to lying. His nose will become longer and longer once he starts lying to others. Because of these characteristics he often finds himself in trouble. Pinocchio undergoes transformations during the novel: he promises The Fairy with turquoise hair to become a real boy, flees with Candlewick to the Land of Toys, becomes a donkey, joins a circus, and becomes a puppet again. In the last chapter, out of the mouth of The terrible dogfish with Geppetto, finally stops being a puppet and becomes a real boy (thanks to the intervention of the Fairy in a dream).
In the novel, Pinocchio is often depicted with a pointy hat, a jacket and a pair of colored, knee-length pants.