Source : Webster's Revised Unabridged Dictionary (1913)

Eruptive \E*rup"tive\, n. (Geol.)
   An eruptive rock.

Eruptive \E*rup"tive\, a. [Cf. F. ['e]ruptif.]
   1. Breaking out or bursting forth.

            The sudden glance Appears far south eruptive through
            the cloud.                            --Thomson.

   2. (Med.) Attended with eruption or efflorescence, or
      producing it; as, an eruptive fever.

   3. (Geol.) Produced by eruption; as, eruptive rocks, such as
      the igneous or volcanic.

Source : WordNet®

eruptive
     adj 1: 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"
            [syn: {volcanic}]
     2: of igneous rock that has solidified beneath the earth's
        surface; granite or diorite or gabbro [syn: {irruptive}, {plutonic}]
     3: erupting or tending to erupt; "a geyser is an intermittently
        eruptive hot spring"