disillusioned (by/with somebody/something) disappointed because the person you admired or the idea you believed to be good and true now seems without value I soon became disillusioned with the job. I feel utterly disillusioned by his refusal to take any action. Her book is the testimony of a disillusioned woman. Later in life he grew rather disillusioned with communism. They felt bitter and disillusioned by the decision.