たるもの / たる

たるもの means "anyone who is a ~": it names a role and then says what that role demands of the person. It follows a noun for a role or status – teacher, parent, leader – and the sentence usually ends in べきだ, なければならない or てはならない.

もの is also written もの者.

たる is an old form of である that survives in writing, speeches and set sayings. In conversation it sounds stiff or mock-solemn, and the everyday way to say the same is きごう〜なら or きごう〜であるいじょう以上.

Adjectives ending in たる

どうどう堂々たる and かっこ確固たる also end in たる, but they are adjectives, not a role plus たる. They describe the noun after them and carry no sense of duty.

Usage notes

These go beyond たるもの at the head of a sentence.

たる before a noun

Without もの, たる links two nouns: "X that comes with being Y". The second noun is usually a quality, duty or condition – ししつ資質, せきにん責任, ぎむ義務, じょうけん条件.

In conversation きごう〜としての says the same: おや親としてのせきにん責任.

たるにふさわしい and たるに足る

たる followed by に and then ふさわしい or たる足る says whether someone measures up to a role: "worthy of being", "fit to be". Here たる stands for "being X", and に links it to the judgement after it.