The Collaborative International Dictionary of English v.0.48:

Anomalous \A*nom"a*lous\, a. [L. anomalus, Gr. ? uneven,
   irregular; 'an priv. + ? even, ? same. See Same, and cf.
   Abnormal.]
   Deviating from a general rule, method, or analogy; abnormal;
   irregular; as, an anomalous proceeding.
   [1913 Webster]

WordNet (r) 3.0 (2006):

anomalous
    adj 1: deviating from the general or common order or type;
           "advanced forms of life may be anomalous in the universe"

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "anomalous":
   aberrant, abnormal, absurd, amorphous, anomalistic, atypical,
   crank, crankish, cranky, crotchety, deviant, deviative, different,
   disproportionate, divergent, dotty, eccentric, erratic,
   exceptional, fey, flaky, foreign, formless, freakish, funny,
   heteroclite, heteromorphic, idiocratic, idiosyncratic, incoherent,
   incommensurable, incommensurate, incompatible, incongruous,
   inconsequent, inconsistent, inconsonant, irreconcilable, irregular,
   kinky, kooky, maggoty, monstrous, nutty, odd, oddball, off-key,
   out of proportion, oxymoronic, paradoxical, peculiar,
   preternatural, prodigious, queer, quirky, screwball, screwy,
   self-contradictory, shapeless, singular, strange, stray, straying,
   subnormal, twisted, unconventional, unnatural, unregular,
   unrepresentative, untypical, wacky, wandering, whimsical