(speak) blaspheme(-er, -mously, -my), defame, rail on, revile, speak evil

Boyd’s Bible Dictionary:

(injurious speaking). Speaking evil of God (Lev. 24:11¹¹And the Israelitish woman's son blasphemed the name of the Lord, and cursed. And they brought him unto Moses: (and his mother's name was Shelomith, the daughter of Dibri, of the tribe of Dan:) (Leviticus 24:11); Psa. 74:18¹⁸Remember this, that the enemy hath reproached, O Lord, and that the foolish people have blasphemed thy name. (Psalm 74:18); Isa. 52:5⁵Now therefore, what have I here, saith the Lord, that my people is taken away for nought? they that rule over them make them to howl, saith the Lord; and my name continually every day is blasphemed. (Isaiah 52:5); Matt. 12:32³²And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come. (Matthew 12:32); Acts 18:6⁶And when they opposed themselves, and blasphemed, he shook his raiment, and said unto them, Your blood be upon your own heads; I am clean: from henceforth I will go unto the Gentiles. (Acts 18:6); Rom. 2:24²⁴For the name of God is blasphemed among the Gentiles through you, as it is written. (Romans 2:24); Col. 3:8⁸But now ye also put off all these; anger, wrath, malice, blasphemy, filthy communication out of your mouth. (Colossians 3:8)). Royalty could be blasphemed (1 Kings 21:10¹⁰And set two men, sons of Belial, before him, to bear witness against him, saying, Thou didst blaspheme God and the king. And then carry him out, and stone him, that he may die. (1 Kings 21:10)). Punished by stoning (Lev. 24:11-14¹¹And the Israelitish woman's son blasphemed the name of the Lord, and cursed. And they brought him unto Moses: (and his mother's name was Shelomith, the daughter of Dibri, of the tribe of Dan:) ¹²And they put him in ward, that the mind of the Lord might be showed them. ¹³And the Lord spake unto Moses, saying, ¹⁴Bring forth him that hath cursed without the camp; and let all that heard him lay their hands upon his head, and let all the congregation stone him. (Leviticus 24:11‑14)).

Concise Bible Dictionary:

In scripture this does not always refer to speaking evil of God, to which the word is now restricted. The same Greek word is translated “railing” in 1 Timothy 6:4⁴He is proud, knowing nothing, but doting about questions and strifes of words, whereof cometh envy, strife, railings, evil surmisings, (1 Timothy 6:4) and Jude 9⁹Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, durst not bring against him a railing accusation, but said, The Lord rebuke thee. (Jude 9); and “evil speaking” in Ephesians 4:31³¹Let all bitterness, and wrath, and anger, and clamor, and evil speaking, be put away from you, with all malice: (Ephesians 4:31), as it might well be rendered elsewhere. Blaspheming the name of the Lord was under the Jewish economy punishable by death: the son of Shelomith who had married an Egyptian, was stoned to death for this sin (Lev. 24:11,14,23¹¹And the Israelitish woman's son blasphemed the name of the Lord, and cursed. And they brought him unto Moses: (and his mother's name was Shelomith, the daughter of Dibri, of the tribe of Dan:) (Leviticus 24:11)
¹⁴Bring forth him that hath cursed without the camp; and let all that heard him lay their hands upon his head, and let all the congregation stone him. (Leviticus 24:14)
²³And Moses spake to the children of Israel, that they should bring forth him that had cursed out of the camp, and stone him with stones. And the children of Israel did as the Lord commanded Moses. (Leviticus 24:23)). The blasphemy against the Holy Ghost was attributing the Lord’s action of casting out demons to the agency of Satan—a sin which should not be forgiven in this age nor in the age to come. The context shows that “the unpardonable sin” refers to this particular form of blasphemy (Matt. 12:24-32²⁴But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils. ²⁵And Jesus knew their thoughts, and said unto them, Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand: ²⁶And if Satan cast out Satan, he is divided against himself; how shall then his kingdom stand? ²⁷And if I by Beelzebub cast out devils, by whom do your children cast them out? therefore they shall be your judges. ²⁸But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you. ²⁹Or else how can one enter into a strong man's house, and spoil his goods, except he first bind the strong man? and then he will spoil his house. ³⁰He that is not with me is against me; and he that gathereth not with me scattereth abroad. ³¹Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men. ³²And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come. (Matthew 12:24‑32)).

Strong’s Dictionary of Greek Words:

Number:

987 (find all occurrences in KJV Bible)

Greek:

βλασφημέω

Transliteration:

blasphemeo

Phonic:

blas-fay-meh’-o

Meaning:

from 989; to vilify; specially, to speak impiously

KJV Usage:

(speak) blaspheme(-er, -mously, -my), defame, rail on, revile, speak evil