taru-adjective, adverb taking the 'to' particle
scared; afraid; trembling with fear
Formal or literary term describing a state of fear or trepidation. Used as a 'taru' adjective or adverb with と. Extremely rare in modern Japanese; encountered only in classical or highly stylized writing.
A passage in a classical text reads, 'trembling with fear, unable to utter a sound.'
panic-stricken; alarmed; frightened (of the masses)
Rare kanji spelling; the word is almost never encountered in modern writing.
Variant kanji spelling, equally rare.
The exact derivation is uncertain. The kanji 恟 is rare and associated with fear; the reduplicated form follows a classical pattern for mimetic or emphatic expressions.