aberrant

comparative more aberrant · superlative most aberrant

1. Differing from the norm.First known use First attested sometime between the mid 16ᵗʰ century and the early 17ᵗʰ century.

   Synonyms: abnormal, exceptional, unusual, abnormal, alien, anomalous, as queer as Dick's hatband, bizarre · Antonyms: normal, regular, true, average, medial, basic, bog-standard, common

2. figurativelysometimesStraying from the right way; deviating from morality or truth.First known use First attested in the mid 18ᵗʰ century.

   Synonyms: devious, errant, immoral, corrupt, corrupted, depraved, lost, dirty-handed · Antonyms: correct, right, straight, chaste, continent, correct, upstanding, delicate

3. biologyDeviating from the ordinary or natural type; exceptional; abnormal.First known use First attested in the mid 19ᵗʰ century.

   The more aberrant any form is, the greater must have been the number of connecting forms which, on my theory, have been exterminated.

   1859, Charles Darwin, On the Origin of the Species

   Antonyms: continuous

plural aberrants

1. A person or object that deviates from the rest of a group.
2. biologyA group, individual, or structure that deviates from the usual or natural type, especially with an atypical chromosome number.

   Also I think other birders realise you are struggling a bit when you start talking about aberrants[.]

   1980, Bill Oddie, Bill Oddie's Little Black Bird Book, page 87

   Synonyms: deviant