johnny-on-the-spot \ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ ̷ ̷ˈ ̷ ̷\noun Usage: usually capitalized J Etymology: from the name Johnny + the phrase on the spot : one who is on hand and ready especially to perform a service or respond to an emergency < luckily he was Johnny-on-the-spot … and was given his highly important post — John Dean >