adverb, adverb taking the 'to' particle
fearfully; timidly; nervously; cautiously
Describes doing something while feeling afraid or anxious, often with hesitation. Frequently used with verbs like する, 見る, 触る, 入る.
彼は恐々暗い部屋に入った。
He fearfully entered the dark room.
初めての料理に、彼女は恐々挑戦した。
She nervously tried cooking for the first time.