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knock out

part of speech: phrase
definition 1: in boxing, to strike (an opponent) and cause that person to fall and be unable to rise within a count of ten.
He knocked out his opponent in the fourth round.He injured his opponent's jaw, but he couldn't knock him out.
definition 2: to cause (someone) to become unconscious, or to powerfully cause to go to sleep.
The falling tree branch knocked the man out.I don't take these pills during the day because they knock me out.
definition 3: to cause complete malfunction or loss of (something)
That last bolt of lightning knocked out the electricity.
definition 4: to cause (someone) to be extremely tired; to exhaust.
All that heavy lifting yesterday really knocked me out.
definition 5: (informal) to cause (someone) to feel a very strong attraction.
Every time I see her, she just knocks me out!