"Good thing we locked the door before the monster got in"

• "Glad that's done"
• Exclamation of exertion
• "That was close!"
• Relieved reaction
• "Man, it's hot!"
• "Boy, is it hot!"
• Cry of relief
• "Thank heaven that's over!"

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
exclamation of astonishment, etc., early 15c., a whistling sound, of imitative origin.

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
interjection EXAMPLES FROM OTHER ENTRIES ▪ Whew , it's hot outside.