Knock v. t.
 1. To strike with something hard or heavy; to move by striking; to drive (a thing) against something; as, to knock a ball with a bat; to knock the head against a post; to knock a lamp off the table.
    When heroes knock their knotty heads together.   --Rowe.
 2. To strike for admittance; to rap upon, as a door.
    Master, knock the door hard.   --Shak.
 3. To impress strongly or forcibly; to astonish; to move to admiration or applause. [Slang, Eng.]
 To knock in the head, or To knock on the head, to stun or kill by a blow upon the head; hence, to put am end to; to defeat, as a scheme or project; to frustrate; to quash. [Colloq.]
 To knock off. (a) To force off by a blow or by beating. (b) To assign to a bidder at an auction, by a blow on the counter. (c) To leave off (work, etc.). [Colloq.]
 To knock out, to force out by a blow or by blows; as, to knock out the brains.
 To knock up. (a) To arouse by knocking. (b) To beat or tire out; to fatigue till unable to do more; as, the men were entirely knocked up. [Colloq.] “The day being exceedingly hot, the want of food had knocked up my followers.” --Petherick. (c) Bookbinding To make even at the edges, or to shape into book form, as printed sheets. (d) To make pregnant.  Often used in passive, "she got knocked up". [vulgar]