atypical
adj.adj. different from what is normal or expected. You use this to describe something that does not fit the usual pattern.
adj. not representative of a type, group, or class; deviating from standard patterns. Often used in scientific or clinical contexts to describe data or behavior.
The warm weather is atypical for this time of year.
The doctor noted that the patient's reaction to the medication was atypical, as most people experience no side effects.
While the artist usually paints in bright, vibrant colors, this somber blue landscape is atypical of her early period and suggests a shift in her creative focus.
From a- + typical.
Typically used as a predicative adjective after linking verbs like 'be' or 'seem', or attributively before a noun.
an untypical behavioratypical behaviorWhile 'untypical' exists, 'atypical' is the standard form in academic and professional English; additionally, 'behavior' is usually uncountable in this context.