The phrase "a disillusion" is not correct in standard English usage; the correct term is "disillusionment." You can use "disillusionment" when referring to the feeling of disappointment resulting from the discovery that something is not as good as one believed it to be.
Example: "After years of working in the industry, she felt a deep sense of disillusionment with the corporate world."
Alternatives: "a sense of disillusionment" or "a feeling of disillusionment."
"There's a disillusion with economic growth.
Artists and audiences were expressing a disillusion with the impersonal systems that dominate modern life, and reaching for the human encounter.
Or when he huffs and puffs thoughtfully about Los Angeles, "a city of big dreams and cruelly inevitable disappointments," where noir is "a disillusion that shadows even the best of times, an alienation that assails the senses like the harsh glitter of mica in the sidewalk on a pitiless Santa Ana day".
Both reflect a disillusion with the scrapping of the education maintenance allowance, the tripling of university tuition fees, the proposal to scrap benefits for those under 21, and attitudes to young people summed up by former Tory cabinet minister Lord Tebbit's view that young unemployed people should be made to pull ragwort from roadsides in return for state support.
The attacks were unprovoked", and assured the world that "we seek no wider war", Ellsberg knew "all of those statements were false" – the beginnings of a disillusion that would eventually lead him to leak the top secret Pentagon Papers seven years later.
Mendelssohn's argument builds off the thesis that the soul is a simple entity and cessation of existence involves a disillusion of one part and then another.
It had been a disillusioning experience.
After a disillusioning focus group with N.Y.U.
And when he took a "disillusioning glimpse at the screen with the naked eye," he shuddered.
Which may be true, but it is a disillusioning statement of intent, undermining what follows.
For generations of aspiring songbirds, including her, the fabled overnight stardom of Ms. Streisand set a disillusioning example.
