bad, evil, harm, ill, noisome, wicked

Concise Bible Dictionary:

Both πονηρός and φαῦλος are translated ‘evil,' but their application in scripture is different, though they may seem to blend. Φαῦλος occurs but four times, referring to doing evil, John 3:20; 5:29²⁰For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved. (John 3:20)
²⁹And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation. (John 5:29); and to the character of what is done as being evil. Titus 2:8⁸Sound speech, that cannot be condemned; that he that is of the contrary part may be ashamed, having no evil thing to say of you. (Titus 2:8); Jas. 3:16¹⁶For where envying and strife is, there is confusion and every evil work. (James 3:16).

πονηοός (from πόνος, ‘labor, sorrow') often refers to the evil nature of the one acting, and the active working out of it. Thus Satan is called that ‘wicked' one. Matt. 13:19, 38¹⁹When any one heareth the word of the kingdom, and understandeth it not, then cometh the wicked one, and catcheth away that which was sown in his heart. This is he which received seed by the way side. (Matthew 13:19)
³⁸The field is the world; the good seed are the children of the kingdom; but the tares are the children of the wicked one; (Matthew 13:38); Eph. 6:16¹⁶Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. (Ephesians 6:16); 1 John 2:13, 14; 3:12¹³I write unto you, fathers, because ye have known him that is from the beginning. I write unto you, young men, because ye have overcome the wicked one. I write unto you, little children, because ye have known the Father. ¹⁴I have written unto you, fathers, because ye have known him that is from the beginning. I have written unto you, young men, because ye are strong, and the word of God abideth in you, and ye have overcome the wicked one. (1 John 2:13‑14)
¹²Not as Cain, who was of that wicked one, and slew his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous. (1 John 3:12). The demons are evil spirits. Luke 7:21; 8:2²¹And in that same hour he cured many of their infirmities and plagues, and of evil spirits; and unto many that were blind he gave sight. (Luke 7:21)
²And certain women, which had been healed of evil spirits and infirmities, Mary called Magdalene, out of whom went seven devils, (Luke 8:2); Acts 19:12, 16¹²So that from his body were brought unto the sick handkerchiefs or aprons, and the diseases departed from them, and the evil spirits went out of them. (Acts 19:12)
¹⁶And the man in whom the evil spirit was leaped on them, and overcame them, and prevailed against them, so that they fled out of that house naked and wounded. (Acts 19:16). The same word is used in reference to the man living in sin in the church at Corinth ― "put away.... that wicked person." 1 Cor. 5:13¹³But them that are without God judgeth. Therefore put away from among yourselves that wicked person. (1 Corinthians 5:13).

κακός, with its many compounds, is a common word for evil and (like πονηρόπς) may apply to the nature or character of those who commit evil, Matt. 21:41; 24:48⁴¹They say unto him, He will miserably destroy those wicked men, and will let out his vineyard unto other husbandmen, which shall render him the fruits in their seasons. (Matthew 21:41)
⁴⁸But and if that evil servant shall say in his heart, My lord delayeth his coming; (Matthew 24:48); Phi. 3:2; Rev. 2:2²I know thy works, and thy labor, and thy patience, and how thou canst not bear them which are evil: and thou hast tried them which say they are apostles, and are not, and hast found them liars: (Revelation 2:2); as well as to their acts and principles, Mark 7:2²And when they saw some of his disciples eat bread with defiled, that is to say, with unwashen, hands, they found fault. (Mark 7:2)1 Cor. 15:33³³Be not deceived: evil communications corrupt good manners. (1 Corinthians 15:33); Col. 3:5⁵Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry: (Colossians 3:5); Rom. 1:30; 13:3³⁰Backbiters, haters of God, despiteful, proud, boasters, inventors of evil things, disobedient to parents, (Romans 1:30)
³For rulers are not a terror to good works, but to the evil. Wilt thou then not be afraid of the power? do that which is good, and thou shalt have praise of the same: (Romans 13:3); 2 Cor. 13:7⁷Now I pray to God that ye do no evil; not that we should appear approved, but that ye should do that which is honest, though we be as reprobates. (2 Corinthians 13:7); though not always with this moral force: see Acts 16:28; 28:5²⁸But Paul cried with a loud voice, saying, Do thyself no harm: for we are all here. (Acts 16:28)
⁵And he shook off the beast into the fire, and felt no harm. (Acts 28:5); ‘harm'; and Luke 16:25²⁵But Abraham said, Son, remember that thou in thy lifetime receivedst thy good things, and likewise Lazarus evil things: but now he is comforted, and thou art tormented. (Luke 16:25), ‘evil things.'

πονηρός would in Latin be industriâ malus, malignus. So the enemy of souls is emphatically ὀ πονηρός, "the evil one." κακός in Latin is malus, improbus, &c., and is used in a very general way, opposed to both

καλός and ἀγαθός, ‘good' 3 John 1:11¹¹Beloved, follow not that which is evil, but that which is good. He that doeth good is of God: but he that doeth evil hath not seen God. (3 John 11) Both κακός and πονηρός occur in Rev. 16:2²And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image. (Revelation 16:2): "noisome (κα.) and grievous (πο.)"; and their nouns κακία and πονηρία, "malice and wickedness." 1 Cor. 5:8⁸Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth. (1 Corinthians 5:8).

Strong’s Dictionary of Greek Words:

Number:

2556 (find all occurrences in KJV Bible)

Greek:

κακός

Transliteration:

kakos

Phonic:

kak-os’

Meaning:

apparently a primary word; worthless (intrinsically, such; whereas 4190 properly refers to effects), i.e. (subjectively) depraved, or (objectively) injurious

KJV Usage:

bad, evil, harm, ill, noisome, wicked