back-to-back

aloof, antisocial, asocial, buttoned-up, cold, cold-eyed, cool, detached, dry, frosty, offish, remote, standoff, standoffish, unbending, unclubbable, unsociable

indrawn, introverted, nongregarious, recessive, reclusive, reserved, unsocial, withdrawn

apathetic, hard, indifferent, unconcerned

clinical, dispassionate, impersonal, professional

disinterested, incurious, uninterested

reticent, silent, taciturn, uncommunicative

diffident, shy, timid

cliquey, cliquish, clubbish

boon, clubbable (also clubable), clubby, companionable, convivial, extroverted (also extraverted), gregarious, outgoing

communicative, expansive, garrulous, talkative

affable, folksy, genial, gracious, hospitable

agreeable, amiable, congenial, kindly, neighborly

cordial, friendly, sociable, social, warm

different, disparate, dissimilar, distinct, distinctive, distinguishable, diverse, nonidentical, other, unalike, unlike

divers, miscellaneous, mixed, several, sundry, variant, varied, various

differentiable, discriminable

alternate, alternative, individual, particular, peculiar, single

disproportionate, divergent, unequal

equal, selfsame

equivalent, tantamount

akin, analogous, comparable, homological, homologous, related

homogeneous, homogenous, uniform

alike, identical, indistinguishable, kin, kindred, like, parallel, same, similar