Webster's Revised Unabridged Dictionary · 1913

Aberrant

Aberrant ({not transcribed}) , adjective

[Latin aberrans, -rantis, present participle of aberrare. See Aberr.]

1.
Wandering; straying from the right way.
2.
(Biology) Deviating from the ordinary or natural type; exceptional; abnormal.
The more aberrant any form is, the greater must have been the number of connecting forms which, on my theory, have been exterminated. — Darwin