From The Collaborative International Dictionary of English v.0.48 [gcide]:
Abnormal \Ab*nor"mal\, a. [For earlier anormal, F. anormal, LL.
anormalus for anomalus, Gr. ?. Confused with L. abnormis. See
Anomalous, Abnormous, Anormal.]
Not conformed to rule or system; deviating from the type;
anomalous; irregular. "That deviating from the type;
anomalous; irregular. " --Froude.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
abnormal
adj 1: not normal; not typical or usual or regular or conforming
to a norm; "abnormal powers of concentration"; "abnormal
amounts of rain"; "abnormal circumstances"; "an abnormal
interest in food" [syn: abnormal, unnatural] [ant:
normal]
2: departing from the normal in e.g. intelligence and
development; "they were heartbroken when they learned their
child was abnormal"; "an abnormal personality" [ant:
normal]
3: much greater than the normal; "abnormal profits"; "abnormal
ambition"