To actively ignore the facts. Someone who's ignorant will understand if you just give them the facts, but someone who ignorates will either put their fingers in their ears and shout "THE WORLD IS FLAT!" or make up other "facts" that conveniently support what they believed to begin with.

To not reply by message for over 24hours

1. feigning ignorance at another's presence, deeds or comments.
2. to willfully avoid a meeting, confrontation or thought.

this is the command to ignore someone on an IRC server and some games such as world of warcraft.

the proper usage is /ignore time username

it is sometimes used IRL

Together with prejudice, the currency of the modern world

Means that you have a lack of knowledge, information or awareness about something in particular....

It Does not mean that someone is ignoring you! O.O

Lack of knowledge