disillusioned
adj.adj. feeling disappointed because you discovered that something is not as good as you believed it was. You lose your faith or respect for an idea, person, or organization.
adj. feeling disappointed and stripped of illusions after discovering that something is less good, valuable, or true than previously believed. Often used predicatively after linking verbs such as 'become', 'grow', or 'feel'.
He became disillusioned with politics after the latest scandal.
Many young voters felt disillusioned when the candidate failed to deliver on his most important campaign promises.
After years of working in the corporate sector, she grew increasingly disillusioned with the profit-at-all-costs mentality and decided to transition into the non-profit world.
Often followed by the preposition 'with' or 'by'.
He is disillusioned about his jobHe is disillusioned with his jobWhile 'about' is occasionally heard, 'with' is the standard preposition used to indicate the source of the disappointment.