nidan verb (upper class) with 'ru' ending (archaic), yodan verb with 'ru' ending (archaic), nidan verb (lower class) with 'ru' ending (archaic), intransitive verb
Archaic verb form; in modern Japanese, 恐れる is used instead. Found in classical literature and fixed expressions like 恐るべき (fearful, formidable). Multiple archaic conjugation patterns (Nidan/Yodan) and marks it are listed as intransitive.
古典では「敵を恐る」のように使われた。
In classical texts, it was used like 'to fear the enemy'.
The form 恐るべき is still used today, as in 'formidable talent'.
Rare archaic variant kanji, with a nuance of dread or apprehension.
Archaic variant kanji, often with a nuance of awe or reverence rather than simple fear.
Archaic verb; the modern form 恐れる developed from it. The exact historical derivation is uncertain, but it is a native Japanese word.