be under no illusion

be under no illusion

To know and understand the reality or truth of a situation. Don't worry, I'm not getting back together with Alex. After all his lies, I'm under no illusion about how he operates.See also: illusion, no

be under no illusion (or illusions)

be fully aware of the true state of affairs. 1992 Christian Scientist Monitor It is crucial to the nation's security…that we be under no illusions about reasons for this zero-loss rate. See also: illusion, no