A beast: see 11.7, which speaks of the beast that came out of the abyss (see also 17.8); the beast here comes out of the sea. It is possible that the two are the same beast, since “the abyss” was often used to refer to the depths of the ocean. In any case the translated text will not establish any clear relationship between the two. Beast, in certain languages where there are only the two categories, domesticated or wild, will need defining phrases such as “a terrible wild animal,” “a huge, horrible animal,” or even “a frightening, savage animal.”
Rising out of the sea: as in 10.2, it is futile to try to identify this as a specific body of water (see Dan 7.3).
Ten horns … seven heads … ten diadems upon its horns: like the dragon (12.3) this marine beast has seven heads and ten horns; but unlike the dragon this beast has a diadem on each of its ten horns. These diadems indicate his royal status. For diadems see 12.3.
A blasphemous name upon its heads: Revised Standard Version translates a Greek text that has the singular name; Good News Translation translates a text that has the plural “names.” The text translated by Good News Bible is preferable, and the translation can be, like Good News Bible, “a name on each of its heads” or “names on its heads.” Here blasphemous means “insulting to God” (see “slander” in 2.9). The common interpretation is that these are names, or titles, that should be used only of God, such as “Lord,” “God,” “Almighty,” “Divine,” “Worthy of Worship.” These seven heads represent seven rulers (see 17.9-10) who claim divine rank. If this interpretation is correct, then the meaning of blasphemous or “insulting” in this context means “to bring dishonor to God,” “to mock God,” or “be an affront to God.” So an alternative translation model for this final clause is “and on each of its heads there was a name that was an affront to (or, mocked) God.”
Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on The Revelation to John. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .