Evil is either moral or natural, moral is evil caused by people (example) and natural is within the universe (example).
Definitions of evil:
John Hick- "physical pain, mental suffering and moral wickedness. The consequence of evil is suffering"
Augustine- a privation of something
McCabe- something not meeting something's expectation
Epicurius- it makes sense for God to be omnipotent and not omnibenevolent, so evil exists, so God has the power to stop it but doesn't want to because He doesn't care. Omnibenevolent and not omnipotent, so evil exists because He wants to stop it but can't because He doesn't have the power to do so. But it doesn't make sense for God to have both qualities and evil…