knockout
noun
°The act of making someone unconscious, or at least unable to come back on their feet within a certain period of time; a TKO.
"The boxer scored a knockout on his opponent."
°Something wildly popular, entertaining, or funny.
"If you've ever had a sack race, you know it's a real knockout for kids and adults alike."
adjective
°Rendering someone unconscious.
"He delivered a knockout blow."
°Stunning; amazing; gorgeous.
"You should have seen her knockout eyes."