[1] : The Collaborative International Dictionary of English v.0.48

attentive \atten"tive\ a^tte^n"ti^v, a. cf. f.
   attentif.
   1. heedful; intent; observant; regarding with care or
      attention.
      1913 webster

   note: attentive is applied to the senses of hearing and
         seeing, as, an attentive ear or eye; to the application
         of the mind, as in contemplation; or to the application
         of the mind, in every possible sense, as when a person
         is attentive to the words, and to the manner and
         matter, of a speaker at the same time.
         1913 webster

   2. heedful of the comfort of others; courteous.
      1913 webster

   syn: heedful; intent; observant; mindful; regardful;
        circumspect; watchful.
        1913 webster -- atten"tively, adv. --
        atten"tiveness, n.
        1913 webster
see also:
atten"tively atten"tiveness 

[2] : WordNet (r) 2.0

attentive
     adj 1: often followed by `to' giving care or attention;
            "attentive to details"; "the nurse was attentive to
            her patient"; "an attentive suitor" ant: inattentive
     2: taking heed; giving close and thoughtful attention; "heedful
        of the warnings"; "so heedful a writer"; "heedful of what
        they were doing" syn: heedful, thoughtful ant: heedless
see also:
inattentive heedful thoughtful heedless 

[3] : Moby Thesaurus II by Grady Ward, 1.0

129 moby thesaurus words for "attentive":
   accommodating, accommodative, accurate, advertent, affable, agile,
   agog, agreeable, alert, alive, all ears, all eyes, assiduous,
   attenuate, awake, aware, bright, cap in hand, careful, cautious,
   ceremonious, circumspect, civil, close, complaisant, concentrated,
   concentrating, conscientious, conscious, considerate, correct,
   courteous, courtly, critical, curious, deferential, delicate,
   demanding, detailed, diligent, dutiful, eager, earnest, exact,
   exacting, exigent, exquisite, fair, fine, finical, finicking,
   finicky, fussy, gallant, graceful, gracious, heedful, helpful,
   honorific, indulgent, intense, intent, intentive, interested, keen,
   lenient, listening, loving, meticulous, mindful, mindful of others,
   minute, narrow, nice, niggling, nimble, obliging, observant,
   observing, on the, on the alert, on the ball, on the job,
   open-eared, open-eyed, openmouthed, particular, polite, precise,
   precisianistic, precisionistic, prompt, punctilious, punctual,
   qui vive, quick, ready, reedy, refined, regardful, religious,
   respectful, rigid, rigorous, scrupulous, scrutinizing, sharp,
   sleepless, slender, slight, slim, smart, solicitous, strict,
   subtle, tactful, tender, tenuous, thoughtful, tolerant, twiggy,
   unblinking, unnodding, unsleeping, unwinking, urbane, wakeful,
   watchful, wide-awake

Attentive >> A Words
Attentive, definition of term: Attentive
attentive_pag1.html