The Collaborative International Dictionary of English v.0.48:

Responsive \Re*spon"sive\ (-s?v), a. [Cf. F. resposif.]
   1. That responds; ready or inclined to respond.
      [1913 Webster]

   2. Suited to something else; correspondent.
      [1913 Webster]

            The vocal lay responsive to the strings. --Pope.
      [1913 Webster]

   3. Responsible. [Obs.] --Jer. Taylor.
      [1913 Webster] -- Re*spon"sive*ly, adv. --
      Re*spon"sive*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

responsive
    adj 1: containing or using responses; alternating; "responsive
           reading"; "antiphonal laughter" [syn: responsive,
           antiphonal]
    2: readily reacting or replying to people or events or stimuli;
       showing emotion; "children are often the quickest and most
       responsive members of the audience" [ant: unresponsive]
    3: reacting to a stimulus; "the skin of old persons is less
       reactive than that of younger persons" [syn: reactive,
       responsive]

Moby Thesaurus II by Grady Ward, 1.0:

182 Moby Thesaurus words for "responsive":
   accessible, acquiescent, adaptable, adaptive, agreeable,
   alacritous, alert, alive, allergic, amenable, anaphylactic,
   answering, antiphonal, ardent, bendable, bending, bouncy, buoyant,
   communicating, communicational, communicative, communional,
   compassionate, compliant, confutative, consenting, content,
   conversational, cooperative, delicate, disposed, docile, ductile,
   eager, echoic, echoing, elastic, emotionable, empathetic, empathic,
   enthusiastic, extensible, extensile, fabricable, facile, fain,
   favorable, favorably disposed, favorably inclined, fictile,
   flexible, flexile, flexuous, formable, formative, forward, game,
   giving, goosy, hyperesthetic, hyperpathic, hypersensitive,
   impressible, impressionable, in the mind, in the mood, inclined,
   influenceable, interacting, interactional, interactive,
   intercommunicational, intercommunicative, intercommunional,
   interresponsive, interrogative, interrogatory, irritable, itchy,
   keen, kindhearted, like putty, limber, linguistic, lissome, lithe,
   lithesome, lively, malleable, minded, moldable, movable, nervous,
   open, open-minded, oral, overrefined, oversensible, oversensitive,
   overtender, passible, persuadable, persuasible, pervious, plastic,
   pliable, pliant, predisposed, prickly, prompt, prone, questioning,
   quick, reacting, reactionary, reactive, ready, ready and willing,
   receptive, reechoing, refined, reflex, reflexive, refluent,
   refutative, rejoining, replying, resilient, respondent, responding,
   retroactionary, retroactive, returning, revulsive, sensible,
   sensile, sensitive, sequacious, shapable, sharp, skittish, soft,
   softhearted, speech, springy, stretch, stretchable, stretchy,
   suasible, submissive, suggestible, supersensitive, supple,
   susceptible, susceptive, swayable, sympathetic, tactful,
   telepathic, tender, tenderhearted, tetchy, thin-skinned, ticklish,
   touchy, tractable, tractile, transmissional, verbal, warm,
   warmhearted, weak, well-disposed, well-inclined, whippy,
   wide-awake, willed, willing, willinghearted, willowy, yielding,
   zealous