| Noun | 1. | berserk - one of the ancient Norse warriors legendary for working themselves into a frenzy before a battle and fighting with reckless savagery and insane fury |
| Adj. | 1. | berserk - frenzied as if possessed by a demon; "the soldier was completely amuck"; "berserk with grief"; "a berserk worker smashing windows"insane - afflicted with or characteristic of mental derangement; "was declared insane"; "insane laughter" |