。
She cleaned the room in a hurry.
Literal
She [topic-は] hurriedly room [object-を] cleaned.
急いで is the te-form of 急ぐ ('to hurry') used adverbially to describe how the next action happens — 'hurriedly,' 'in a rush.' This is one of Japanese's standard tricks for forming manner adverbs: take a verb, put it in te-form, and chain it before the main verb. Compare 笑って言う ('say with a laugh'), 立って話す ('stand and talk'), 走って帰る ('run home'). The pattern only works smoothly with verbs that name a manner or simultaneous activity rather than a separate event.