originally an apple from the tree of knowledge of good and evil in the Garden of Eden; it is now used to refer to anything that is tempting but dangerous (as sexuality)
having or showing great excitement and interest; "enthusiastic crowds filled the streets"; "an enthusiastic response"; "was enthusiastic about taking ballet lessons"
in constant agitation; "a seething flag-waving crowd filled the streets"; "a seething mass of maggots"; "lovers and madmen have such seething brains"- Shakespeare