This descriptive name was given to Satan because he is the chief and foremost slanderer and false accuser of Jehovah, his good word, and his holy name. The Greek di·aʹbo·los means “slanderer.” (Compare Lu 16:1, where the related verb di·a·balʹlo occurs.)​—See SATAN.

Down through the centuries the Devil has demonstrated that he is the arch-opposer of both God and man. He disputed with Michael over the body of Moses (Jude 9); showed he has power to ensnare others (1Ti 3:7; 2Ti 2:26); used people such as the false religious leaders, Judas Iscariot, and Bar-Jesus as his children (Joh 8:44; 13:2; Ac 13:6, 10); oppressed persons beyond the cure of the physicians (Ac 10:38); had righteous ones thrown into prison (Re 2:10); and even had the means to cause untimely death (Heb 2:14). Christians are, therefore, admonished not to give this Slanderer of God an opening by continuing in a provoked state. (Eph 4:27) “Keep your senses, be watchful,” Peter warns. “Your adversary, the Devil, walks about like a roaring lion, seeking to devour someone.”​—1Pe 5:8.

There are other instances in the original text of the Christian Greek Scriptures where the word  di·aʹbo·los occurs but does not refer to Satan, so the word is properly rendered “slanderer.” For example, in referring to Judas, Jesus said to the 12, “One of you is a slanderer” (Joh 6:70); women in the congregation were cautioned not to be slanderous (1Ti 3:11; Tit 2:3); that “men will be . . . slanderers” is one of the evidences of “the last days.”​—2Ti 3:1-5.

Jehovah’s law to the nation of Israel forbade them to slander one another. (Le 19:16) The tenor of the entire Bible is against such misuse of the tongue.​—2Sa 19:27; Ps 15:3; 101:5; Pr 11:13; 20:19; 30:10; Jer 6:28; 9:4.