He knocked on wood for luck.

Meaning: He hit a piece of wood in the hope that it would bring him good fortune.

Choice of Words: Knocked means to hit something with a sharp, quick blow. On is a preposition that indicates a surface or location. Wood is a hard, fibrous material that is found in trees and other plants. For is a preposition that indicates a purpose or reason. Luck is a positive outcome that is believed to be caused by chance.

Alternative Expressions

Related Expressions

• The mischievous cat knocked over the glass of milk.
• The cat jumped on the table and knocked over the vase.
• The clumsy dog knocked over the vase.
• The cat jumped onto the table and knocked over the vase.
• The cat jumped onto the table and knocked the vase over.
• The mischievous cat knocked over the vase with its playful tail.
• I knocked on the door loudly.
• The cat jumped on the table and knocked the vase over.
• The cat jumped onto the table and knocked over a glass of water.
• The cat learned its lesson and never knocked over a glass of water again.