adverb, adverb taking the 'to' particle
smoothly; easily; without a hitch
Describes something proceeding fluidly and without difficulty, such as speaking, writing, or a task. Often used with verbs like 話す, 書く, 進む.
彼女は日本語をすらすら話す。
She speaks Japanese fluently.
仕事がすらすら進んだ。
The work went smoothly.