knock out

1. Also, knock out cold . Render unconscious by a blow or some other means. For example, It was just a swinging door, but it knocked her out , or Just one of those sleeping pills can knock you out cold . [Late 1500s]

2. Make tired, exhaust, as in That sightseeing tour knocked me out .

3. Render useless or inoperative, as in The storm knocked out the power .

4. See knock off , def. 2.

5. See knock oneself out .