Definition: "Naturally, they may fall off a cliff"
This is a cryptic definition - the entire clue serves as both definition and wordplay, using descriptive language that points to the answer in a non-obvious way.
Think about what literally happens when earth and rock naturally fall off a cliff face. The phrase describes both the physical process and gives you the geological term for this phenomenon.
Answer: LANDSLIPS | This is a not-very-cryptic definition where the entire clue describes what landslips are - geological events where land naturally falls off cliff faces or slopes.