doodle

/ˈduːdəl/
noun
  1. A simple, aimless drawing or scribble.
    • The margins of the report were covered in doodles.
    • She showed me a doodle she made of a cat wearing a hat.
    • His notebook was full of tiny doodles of stars and smiley faces.
verb
  1. To draw or scribble aimlessly, especially while thinking or listening.
    • She likes to doodle in the margins of her notebook during class.
    • The artist began to doodle random shapes before starting the real painting.
    • While on the phone, he would often doodle little flowers on a scrap of paper.