Yoga Sutra 1.8

विपर्ययो मिथ्याज्ञानमतद्रूपप्रतिष्ठम् ॥८॥

viparyayo mithyājñānamatadrūpapratiṣṭham ॥8॥

viparyayah:misconception; mithyā:false, illusory; jñānam:knowledge; atat:not its own; rūpa:form; pratiṣṭham:based

Wrong conception is false knowledge which is not based on its own form.

OR

Misconception is illusory knowledge based on mistaking a particular form for something completely different.

Viparyaya - misconception is false knowledge which we need to overcome. For example, when we mistake a rope for a snake, the knowledge is incorrect, because it's a rope mistaken for a snake. This can be avoided with adequate light.

Hence it is important that we don't mistake things for something else.

Viparyaya is also known as avidya, because it is based on a misunderstanding of the real nature of purusha and prakriti. It can be replaced by viveka which brings correct understanding of the true nature of purusha and prakriti.

References

• Four Chapters on Freedom by Swami Satyananda Saraswati, published in 1976.
• Viparyaya