'Evil' in the Bible

Beware, brothers, lest perhaps there be in any one of you an evil heart of unbelief, in falling away from the living God;

But solid food is for those who are full grown, who by reason of use have their senses exercised to discern good and evil.

let's draw near with a true heart in fullness of faith, having our hearts sprinkled from an evil conscience, and having our body washed with pure water,