失しつ念ねん

noun, noun or participle which takes 'suru', transitive verb

forgetting; lapse of memory

Formal or written term for forgetting something one should have remembered; often used in business or official contexts to acknowledge an oversight.

• 会かい議ぎの予よ定ていを失しつ念ねんしておりました。

  I had forgotten about the meeting schedule.

• 重じゅう要よう