Source : Webster's Revised Unabridged Dictionary (1913)

Intensive \In*ten"sive\, a. [Cf. F. intensif. See {Intense}.]
   1. Stretched; admitting of intension, or increase of degree;
      that can be intensified. --Sir M. Hale.

   2. Characterized by persistence; intent; unremitted;
      assiduous; intense. [Obs.] --Sir H. Wotton.

   3. (Gram.) Serving to give force or emphasis; as, an
      intensive verb or preposition.

Intensive \In*ten"sive\, n.
   That which intensifies or emphasizes; an intensive verb or
   word.

Intensive \In*ten"sive\, a. (Agric.)
   Designating, or pertaining to, any system of farming or
   horticulture, usually practiced on small pieces of land, in
   which the soil is thoroughly worked and fertilized so as to
   get as much return as possible; -- opposed to {extensive}.

Source : WordNet®

intensive
     n : a modifier that has little meaning except to intensify the
         meaning it modifies; "`up' in `finished up' is an
         intensifier"; "`honestly' in `I honestly don't know' is
         an intensifier" [syn: {intensifier}]

intensive
     adj 1: characterized by a high degree or intensity; often used as a
            combining form; "the questioning was intensive";
            "intensive care"; "research-intensive"; "a
            labor-intensive industry"
     2: tending to give force or emphasis; "an intensive adverb"
     3: of agriculture; intended to increase productivity of a fixed
        area by expending more capital and labor; "intensive
        agriculture"; "intensive conditions" [ant: {extensive}]