adjective

unusual; not typical.

late claims will only be accepted in exceptional circumstances

unusual,uncommon,abnormal,atypical,extraordinary,out of the ordinary,out of the way,rare,singular,unprecedented,unexpected,surprising,strange,odd,queer,bizarre,freakish,anomalous,peculiar,inconsistent,deviant,divergent,aberrant,unheard of,out of the common,weird,way out,freaky,something else,seldom,unexampled

noun

an item in a company’s accounts arising from its normal activity but much larger or smaller than usual.