κακός, πονηρός, φαῦλος.These words may be used with very little distinction of meaning, but often the difference is marked. κακός frequently means evil rather negatively, referring to the absence of the qualities which constitute a person or thing what it should be or what it claims to be. It is also used meaning evil in a moral sense. It is a general antithesis to ἀγαθός. πονηρός is a word at once stronger and more active, it means mischief-making, delighting in injury, doing evil to others, dangerous, destructive. κακός describes the quality according to its nature, πονηρός, according to its effects. φαῦλος is the bad chiefly as the worthless, the good for nothing.