落書き

1. Origins, structure, and basic meaning

• Structure: 落書き is read as らくがき and is a noun and する verb covering both a casual doodle and unauthorized writing or drawing on a wall.
• Basic usage: A notebook example appears in 落書きをする, while removing it from a wall appears in 壁の落書きを消す.

2. Common pitfalls and similar expressions

• Two meanings shaped by context
  • A casual drawing in a notebook is a doodle, while marks on a public wall may be graffiti.
• Difference from 絵
  • 絵 broadly denotes an intentionally made picture, whereas 落書き carries a casual or unauthorized character.