さっかく錯覚sakkaku
1.

A phenomenon where a person perceives something differently from reality, often leading to misunderstandings or misinterpretations of sensory information.

2.

A mental experience characterized by a significant discrepancy between perceived objects and the actual characteristics of those objects, often resembling a distortion of reality.

3.

An erroneous perception that creates the impression of an existence or event that does not actually occur, sometimes leading to a false sense of experience.

4.

A cognitive misjudgment that causes someone to believe in the presence of something based on misleading sensory inputs, similar to a deceptive memory or belief.

Example:

これはあれよりも長いように見えるが、錯覚だ。