Abnormal (adjective)
Not conforming to rule or system; deviating from the usual or normal type. First attested around the mid 19th century.page=6
Abnormal (adjective)
Of or pertaining to that which is irregular, in particular, behaviour that deviates from norms of social propriety or accepted standards of mental health. First attested around the early 20th century.
Abnormal (noun)
A person or object that is not normal.
Unnormal (adjective)
Not normal.
Wiktionary
Abnormal (adjective)
deviating from what is normal or usual, typically in a way that is undesirable or worrying
“the illness is recognizable from the patient’s abnormal behaviour”
Oxford Dictionary