The Collaborative International Dictionary of English v.0.48:

Infelicitous \In`fe*lic"i*tous\, a.
   Not felicitous; unhappy; unfortunate; not fortunate or
   appropriate in application; not well said, expressed, or
   done; as, an infelicitous condition; an infelicitous remark;
   an infelicitous description; infelicitous words.
   [1913 Webster]

WordNet (r) 3.0 (2006):

infelicitous
    adj 1: not appropriate in application; defective; "an
           infelicitous remark"; "infelicitous phrasing"; "the
           infelicitous typesetting was due to illegible copy" [ant:
           felicitous]
    2: marked by or producing unhappiness; "infelicitous
       circumstances"; "unhappy caravans, straggling afoot through
       swamps and canebrakes"- American Guide Series [syn:
       infelicitous, unhappy]

Moby Thesaurus II by Grady Ward, 1.0:

121 Moby Thesaurus words for "infelicitous":
   Doric, bad, barbaric, barbarous, cacophonous, careless, clumsy,
   coarse, crude, doggerel, dysphemistic, erroneous, faulty, futile,
   graceless, gross, harsh, ill-adapted, ill-advised, ill-assorted,
   ill-chosen, ill-considered, ill-fitted, ill-matched, ill-seasoned,
   ill-sorted, ill-suited, ill-timed, impolitic, imprecise, improper,
   impure, in bad taste, inadmissible, inadvisable, inapplicable,
   inapposite, inappropriate, inapt, inauspicious, inconcinnate,
   inconcinnous, incongruous, inconvenient, incorrect, indecorous,
   inelegant, inept, inexpedient, inopportune, intempestive,
   intrusive, irrelevant, late, loose, low, mal a propos, maladjusted,
   malapropos, misjoined, mismatched, mismated, misplaced, mistimed,
   off base, out of character, out of joint, out of keeping,
   out of line, out of phase, out of place, out of proportion,
   out of season, out of time, out of tune, outlandish, premature,
   rude, slipshod, slovenly, solecistic, tasteless, too late,
   too soon, unadapted, unapt, unbecoming, unbefitting, uncourtly,
   uncouth, undesirable, undignified, uneuphonious, unfavorable,
   unfelicitous, unfit, unfitted, unfitting, unfortunate, ungraceful,
   ungrammatic, unhandy, unhappy, unlucky, unmeet, unpolished,
   unprofitable, unpropitious, unqualified, unready, unrefined,
   unripe, unseasonable, unseemly, unsuitable, unsuited, untimely,
   untoward, unwise, vulgar, wrong