igneous rock produced by eruption and solidified on or near the earth's surface; rhyolite or andesite or basalt; "volcanic rock includes the volcanic glass obsidian"
explosively unstable; "a volcanic temper"
relating to or produced by or consisting of volcanoes; "volcanic steam"; "volcanic islands such as Iceland"; "a volcanic cone is a conical mountain or hill built up of material from volcanic eruptions"
characterized by forceful and energetic action or activity; "a vigorous hiker"; "gave her skirt a vigorous shake"; "a vigorous campaign"; "a vigorous foreign policy"; "vigorous opposition to the war"
strong and active physically or mentally; "a vigorous old man who spent half of his day on horseback"- W.H.Hudson
so great in size or force or extent as to elicit awe; "colossal crumbling ruins of an ancient temple"; "has a colossal nerve"; "a prodigious storm"; "a stupendous field of grass"; "stupendous demand"