To thrash, to beat up, to batter, to clobber. Derived from the noun дубина (cudgel, club), combined with the intensive prefix от- (denoting completion or thorough execution). In everyday street slang and colloquial speech, it is a highly expressive, aggressive verb that means to severely beat someone up, typically with fists, feet, or an object, inflicting significant physical pain (его вчера знатно отдубасили за баром — “he got thoroughly thrashed behind the bar yesterday”).
На второй песне группы «День и ночь» между сценой и лавками началась драка. Несколько гопников отдубасили волосатого чувака.
During the second song of the group “Day and Night” a fight erupted between the scene and the benches. A few punks were roughing up a hairy bloke.
(Владимир Козлов, Лето девять один)
