supererogatory
adj. 額外的,超出職務的
1. more than is needed, desired, or required;
It was supererogatory for her to gloat ( Mary McCarthy )
她也在一旁幸災樂禍地看得出神,真是多餘 ( 瑪麗麥卡錫 )
It was supererogatory of her to gloat.
她沒必要幸災樂禍.
needless