evil, wicked: bad in a way that actively works harm
This is the New Testament's strongest everyday word for what is bad. Unlike a milder word that simply means defective or low quality, this word usually carries an active, working malice: it names evil that does damage, not merely evil that falls short. So it describes wicked people, a corrupt generation, sinful deeds, scheming thoughts, and the present age set against God.
The same word also reaches the plainer end of the scale, where the badness is harmful or ruinous without being a moral charge: bad fruit a diseased tree produces, a painful and grievous sore, a slander brought against someone. Greek lets one word run from a rotten piece of fruit to a rotten heart because the common thread is the harm done.
A distinct idiom sits inside this range. The Bible speaks of an evil eye, which in that culture meant not an occult curse but a grudging, stingy, envious outlook that begrudges others good. So a person with a bad eye is the opposite of generous.
The senses below sort these uses, but they are shades of one core idea, not separate words. The reader should hear an edge of active harm wherever this word appears, and decide from the context whether the harm is moral wickedness, painful defect, or grudging stinginess.