The Collaborative International Dictionary of English v.0.48:

Directive \Di*rect"ive\, a. [LL. directivus: cf. F. directif.]
   1. Having power to direct; tending to direct, guide, or
      govern; showing the way. --Hooker.
      [1913 Webster]

            The precepts directive of our practice in relation
            to God.                               --Barrow.
      [1913 Webster]

   2. Able to be directed; manageable. [Obs.]
      [1913 Webster]

            Swords and bows
            Directive by the limbs.               --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

directive
    adj 1: showing the way by conducting or leading; imposing
           direction on; "felt his mother's directing arm around
           him"; "the directional role of science on industrial
           progress" [syn: directing, directional, directive,
           guiding]
    n 1: a pronouncement encouraging or banning some activity; "the
         boss loves to send us directives"

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "directive":
   actuating, admonitory, advisory, aimable, aimed, animating, causal,
   causative, cautionary, chief, commanding, communication,
   compelling, consultative, consultatory, controlling, decree,
   decretal, decretive, decretory, dictating, didactic, directed,
   directing, direction, directional, directorial, directory,
   dirigible, driving, edict, exhortative, exhortatory, expostulative,
   expostulatory, general orders, governing, guidable, guiding, head,
   hortative, hortatory, impelling, imperative, impulsive, inducive,
   instruction, instructive, jussive, leadable, leading, managerial,
   managing, mandating, memo, monitorial, monitory, moralistic,
   motivating, motivational, motive, moving, notice, obligating,
   on the mark, on the nose, peremptory, pointable, preachy, precept,
   preceptive, prescript, prescription, prescriptive, pressing,
   recommendatory, regulating, regulation, regulative, regulatory,
   remonstrant, remonstrative, remonstratory, rule, ruling,
   sententious, steerable, trainable, ukase, urgent, warning,
   well-aimed, well-directed, word