Chalkiness is the quality of being like chalk, or of having chalk in it — that dry, white, powdery feel or look. If a sauce has chalkiness, it feels dusty in your mouth, not smooth. If soil has chalkiness, it contains a lot of chalk, a soft white rock. Cheap chocolate, old paint, or even a smile can be talked about this way: the chalkiness of the chocolate means it tastes powdery. Though actually, the everyday word is the adjective chalky; chalkiness is the noun you use when you talk about that dry white powderiness as a thing in itself. You meet it in food notes, geology, and art more than in beginner chat.