Avarana (आवरण) is a Sanskrit term that translates as 'covering' or 'obstruction'.
It is considered to be one of the three defects of the mind that hinder spiritual progression.
Avarana is a veil of ignorance that dulls the mind and prevents people from seeing their true/higher self.
[1] Avarana is identified as one of the attributes of maya in Advaita Vedanta.
Adi Shankara mentions in his Vivekacūḍāmaṇi (verses 115–118) that avarana is an effect of the tamas guna.