Avidyā is a Sanskrit word whose literal meaning is ignorance, misconceptions, misunderstandings, incorrect knowledge, and it is the opposite of Vidya.
[2] The term includes not only ignorance out of darkness, but also obscuration, misconceptions, mistaking illusion to be reality or impermanent to be permanent or suffering to be bliss or non-self to be self (delusions).
[11] Isha Upanishad refers to vidya and avidya in verses 9-11: It's far different from knowledge, they say, Different also from ignorance, we're told- so have we heard from wise men, who have explained it to us.
Because of their passion, they do not understand, these people who are given to rites"Avidya is described in the Yoga Sutras by Patanjali, as the first of the five kleshas, the knots of affliction, and the productive field of all them that follow.
Avidya stands for that delusion which breaks up the original unity (refer: nonduality) of what is real and presents it as subject and object and as doer and result of the deed.
[20] Adi Shankara says in his Introduction to his commentary on the Brahma Sutras, Owing to an absence of discrimination, there continues a natural human behaviour in the form of 'I am this' or 'This is mine'; this is avidya.
The ascertainment of the nature of the real entity by separating the superimposed thing from it is vidya (knowledge, illumination).In the view of his later followers, avidya cannot be categorized either as 'absolutely existent' or as 'absolutely non-existent'.