(of people or behaviour) overly bold or self-assertive to the point of being insensitive, tactless or impudent; shameless.
Example: "A brash young businessman; a brash tabloid; a brash sense of humour"
(of actions) overly bold, impetuous or rash.
(of things) bold, bright or showy, often in a tasteless way.
Example: "Brash colours; a brash perfume"
Brittle (said e.g. of wood or vegetables).