If you scribble something, you write it quickly and roughly. She scribbled a note to tell Mum she'd gone out As I scribbled in my diary the light went out
{f} write quickly and sloppily, scrawl; doodle, create meaningless pictures or scrawl
To write hastily or carelessly, without regard to correctness or elegance; as, to scribble a letter
If you scribble down something, you write it quickly or roughly. I attempted to scribble down the names He took my name and address, scribbling it down in his notebook