に足る / に足りる【にたる / にたりる】

The grammar pattern に足る (and its ichidan variant に足りる) means "worthy of ~", "worth ~ing", or "sufficient to ~". It attaches to a verb (dictionary form) or noun to express that something meets a certain standard or threshold of significance.

This is a formal, literary expression most commonly found in written Japanese, speeches, and formal evaluations. It carries the nuance that something has enough value or importance to deserve a particular action or judgment.

Basic usage

The pattern is used with verbs like しんらい信頼する (to trust), そんけい尊敬する (to respect), ちゅうもく注目する (to pay attention to), おどろく驚く (to be surprised), and ろんじる論じる (to discuss).

に足る vs. に足りる

Both forms are used, but に足る (classical/文語 form) is more common in set phrases and formal writing. に足りる (modern ichidan form) is also acceptable and sometimes seen in slightly less formal contexts, though both remain literary.

Negative form

The negative forms に足らない / に足りない are very common, meaning "not worthy of ~" or "not worth ~ing." The phrase とる取るにたらない足らない ("trivial; not worth considering") is an especially well-known set expression.

Nuance

Unlike the more casual 〜～にあたいする値する (which also means "worthy of"), に足る carries a more classical, dignified tone. It is used when evaluating someone's character, the significance of an event, or the merit of an argument.