The Collaborative International Dictionary of English v.0.48:

Insular \In"su*lar\, a. [L. insularis, fr. insula island: cf. F.
   insulaire. See Isle.]
   [1913 Webster]
   1. Of or pertaining to an island; of the nature, or
      possessing the characteristics, of an island; as, an
      insular climate, fauna, etc.
      [1913 Webster]

   2. Of or pertaining to the people of an island; narrow;
      circumscribed; illiberal; contracted; as, insular habits,
      opinions, or prejudices.
      [1913 Webster]

            The penury of insular conversation.   --Johnson.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Insular \In"su*lar\, n.
   An islander. [R.] --Berkeley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

insular
    adj 1: relating to or characteristic of or situated on an
           island; "insular territories"; "Hawaii's insular culture"
    2: suggestive of the isolated life of an island; "an exceedingly
       insular man; so deeply private as to seem inaccessible to the
       scrutiny of a novelist"- Leonard Michaels
    3: narrowly restricted in outlook or scope; "little sympathy
       with parochial mentality"; "insular attitudes toward
       foreigners" [syn: insular, parochial]

Moby Thesaurus II by Grady Ward, 1.0:

160 Moby Thesaurus words for "insular":
   alien, alienated, alone, aloof, apart, archipelagian, archipelagic,
   asunder, authoritarian, bigot, bigoted, bipartite, borne,
   circumscribed, closed, companionless, confined, constricted,
   cramped, creedbound, deaf, deaf to reason, detached, dichotomous,
   disconnected, discontinuous, discrete, disjunct, disrelated,
   dissociated, distinct, divergent, ethnocentric, exceptional,
   excluding, exclusive, exclusory, exotic, extraneous, fanatical,
   foreign, friendless, geographically limited, hidebound, homeless,
   illiberal, in a backwater, in two, inadmissible, incoherent,
   incommensurable, incomparable, independent, insulated, irrelative,
   island, island-dotted, island-dweller, islanded, islander,
   islandish, islandlike, islandman, islandologist, islandy, islesman,
   isleted, isolated, kithless, limited, little, little-minded, local,
   localized, lone, lonely, lonesome, mean, mean-minded,
   mean-spirited, narrow, narrow-hearted, narrow-minded,
   narrow-souled, narrow-spirited, nearsighted, noncohesive,
   of a place, other, out-of-the-way, out-of-the-world, outlandish,
   parochial, partitioned, petty, preclusive, prescriptive,
   preventive, prohibitive, provincial, purblind, quarantined,
   regional, remote, removed, restricted, restrictive, retired,
   rootless, seagirt, secluded, seclusive, sectarian, sectional,
   segregate, segregated, segregative, select, selective, separate,
   separated, separative, shortsighted, shut off, single-handed,
   small, small-minded, small-town, snobbish, solitary, solo,
   straitlaced, strange, stuffy, topical, unabetted, unaccompanied,
   unaffiliated, unaided, unallied, unassisted, unassociated,
   unattached, unattended, uncatholic, uncharitable, unconnected,
   unescorted, unfrequented, ungenerous, unjoined, unliberal,
   unrelatable, unrelated, unseconded, unsupported, unvisited,
   vernacular, withdrawn, xenophobic