〜たりとも

A strongly emphatic negative used with the smallest unit — 一日, 一円, 一瞬, 一人 — to insist that not even that much is permitted or possible. It is formal and rather rigid, appearing in speeches, slogans, rules and the language of determination; 何人たりとも ('no one whatsoever') is a set exception. The sentence must end in a negative, a prohibition or 〜な.

• 締め切りまで、一日たりとも休めない。

  しめきりまで、いちにちたりともやすめない。

  Until the deadline I can't take even a single day off.

• 寄付金は一円たりとも無駄にはできない。

  きふきんはいちえんたりともむだにはできない。

  Not a single yen of the donations may be wasted.

• 本番では一瞬たりとも気を抜くな。

  ほんばんではいっしゅんたりともきをぬくな。

  During the actual performance, don't let your guard down for even a moment.