ig·no·rance

/ˈıgnərəns/ noun

: a lack of knowledge, understanding, or education : the state of being ignorant

[noncount]

His racist attitudes were born out of ignorance.

— often + of

Ignorance of the law is no excuse (for violating it).

Their decisions were made in ignorance of [=without knowing] the true nature of the situation.

When asked about the reasons for these drastic changes, she pleaded/pled ignorance. [=she said that she did not know the reasons]

[singular]

an appalling ignorance about/of other cultures

ignorance is bliss

— used to say that a person who does not know about a problem does not worry about it