under the impression

Idioms  

1. Thinking, assuming, or believing something, as in I was under the impression that they were coming today. This idiom often suggests that the idea or belief one had is mistaken. [Mid-1800s]

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Example Sentences

Boos rained down from the chilly New York crowd, which had been foolishly under the impression they might see the Mets win.

From The Wall Street Journal • Apr. 22, 2026

She claimed that she was mistakenly under the impression that her case would then be sent to appeal and noted that she has the documented verbal comprehension of a second-grader.

From Los Angeles Times • Mar. 31, 2026

If you haven’t yet watched the limited series, you may be under the impression that this is a spoiler.

From Salon • Nov. 19, 2025

The journalists were waiting around under the impression that ICE was going to make an arrest when the court let out.

From Slate • Oct. 10, 2025

“I’m sure you all need your rest...but there are wedding presents stacked in my room that need sorting out and I was under the impression that you had agreed to help.”

From "Harry Potter and the Deathly Hallows" by J.K. Rowling