Hasty, hurried handwriting (scribble); writing done quickly that may be messy or hard to read.
メモは走り書きで読みにくい。
The memo is written in a hurried hand and is hard to read.
彼女は急いで走り書きした住所を渡した。
She handed over the hastily written address.
走り書きの文字から彼の焦りが伝わる。
You can sense his haste from the hurried handwriting.