～であろう

• Reading: であろう
• Romaji: dearou
• Formation: Noun / Na-adj + であろう / Verb plain form + であろう

Meaning

A formal auxiliary indicating the writer's conjecture or supposition, typically not based on specific evidence. It is the written/formal equivalent of だろう.

であろう is the formal counterpart of だろう and is widely used in academic papers, newspaper articles, formal essays, and speeches. It attaches to nouns and な-adjectives via で + あろう, and can also follow verbs and い-adjectives in their plain forms. While だろう is acceptable in both spoken and written Japanese, であろう is almost exclusively found in written contexts or highly formal speeches. It conveys a measured, authoritative tone of supposition. The form can also appear as であろうか in rhetorical questions, adding a contemplative nuance.

Examples

1. この技術は将来さらに発展するであろう。 This technology will likely develop further in the future.
2. 人口減少は日本の最大の課題であろう。 Population decline is probably Japan's greatest challenge.
3. この傾向は今後も続くであろう。 This trend will likely continue going forward.

Usage Guide

Context: written, academic, formal speech

Tone: authoritative

Do Say

• この問題の解決には時間がかかるであろう。
• 次の世代にとって環境保護は最も重要な課題であろう。
• 彼の功績は長く記憶されるであろう。

Don't Say

• 明日は晴れであろう。(Using であろう in everyday conversation — sounds stiff and unnatural in casual speech) → 明日は晴れだろう。
• あの店のラーメンはおいしいであろう。(Using であろう after い-adjective with unnecessary formal tone for a trivial topic) → あの店のラーメンはおいしいだろう。

Origin & History

Composed of the copula で (from である) and あろう (volitional/conjectural form of ある). It is a formal written style that evolved from classical Japanese patterns of conjecture.

Cultural Context

Generation: All ages

Social background: Universal