1. An exclamation used to express surprise, excitement, or to attract attention.
Usage: informal; often used in phrases like 'hoo-ha' or 'hoo-boy'

1. The sound made by an owl or a similar hooting sound.
Usage: informal; often used onomatopoetically

Examples

• Hoo! That was a close call!
• The owl let out a loud hoo in the night.
• Hoo-boy, did you see that?
• She heard the hoo of an owl from the forest.
• Hoo-ha! What a surprise party that was!