。
She washed the blouse quickly.
Literal
She [topic-は] that blouse [object-を] quickly washed.
すばやく is the adverbial form of すばやい ('quick, swift, agile'); the continuative く form turns the i-adjective into an adverb modifying the verb. すばやい emphasizes speed-with-skill or speed-with-purpose — distinct from plain 速い ('fast'), which describes raw speed. ブラウス is the standard loanword for women's blouse; like many clothing terms (シャツ, スカート, ジャケット), katakana imports dominate this domain.