Thumbing can refer to several different things depending on the context:

1. Hitchhiking (Thumb a Ride): Thumbing often refers to the act of sticking out your thumb by the side of a road in an attempt to get a ride from passing vehicles, especially when you’re a pedestrian trying to catch a lift from drivers going in the same direction.
2. Scrolling Through Content: In the context of technology and touch interfaces, “thumbing” might mean using your thumb to scroll through digital content on a touchscreen device, such as swiping up or down to move through a webpage or app.
3. Expressing Approval or Disapproval: Sometimes, “thumbing” can mean giving a thumbs-up or thumbs-down gesture to indicate approval or disapproval of something, usually in a non-verbal manner.
4. Quick Reading or Skimming: Informally, “thumbing through” a book or document could refer to quickly flipping through its pages, often to get a rough idea of its content rather than reading it thoroughly.
5. Texting or Typing: In a texting or typing context, “thumbing” could refer to using your thumbs to input text on a mobile device’s virtual keyboard.