1. the action or sound of something moving up and down or back and forth rapidly

1. moving up and down or back and forth rapidly
Usage: present participle of flap

Examples

• The bird was flapping its wings frantically.
• I could hear the flapping of the flag in the wind.
• The tent was flapping loudly in the storm.
• She was flapping her arms to get our attention.
• The constant flapping of the loose shutter kept me awake.
• The duck started flapping across the water to take off.