From WordNet (r) 2.0 (August 2003) [wn]:
knock
n 1: the sound of knocking (as on a door or in an engine or
bearing); "the knocking grew louder" [syn: knocking]
2: negative criticism [syn: roast]
3: a vigorous blow; "the sudden knock floored him"; "he took a
bash right in his face"; "he got a bang on the head" [syn:
bash, bang, smash, belt]
4: a bad experience; "the school of hard knocks"
5: the act of hitting vigorously; "he gave the table a whack"
[syn: belt, rap, whack, whang]
v 1: deliver a sharp blow or push :"He knocked the glass clear
across the room" [syn: strike hard]
2: rap with the knuckles; "knock on the door"
3: knock against with force or violence; "My car bumped into
the tree" [syn: bump]
4: make light, repeated taps on a surface; "he was tapping his
fingers on the table impatiently" [syn: tap, rap,
pink]
5: sound like a car engine that is firing too early; "the car
pinged when I put in low-octane gasoline"; "The car pinked
when the ignition was too far retarded" [syn: pink,
ping]
6: find fault with; express criticism of; point out real or
perceived flaws; "The paper criticized the new movie";
"Don't knock the food--it's free" [syn: criticize,
criticise, pick apart] [ant: praise]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Knock \Knock\ (n[o^]k), 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.
[1913 Webster]
When heroes knock their knotty heads together.
--Rowe.
[1913 Webster]
2. To strike for admittance; to rap upon, as a door.
[1913 Webster]
Master, knock the door hard. --Shak.
[1913 Webster]
3. To impress strongly or forcibly; to astonish; to move to
admiration or applause. [Slang, Eng.]
[Webster 1913 Suppl.]
4. To criticise; to find fault with; to disparage. "Don't
knock it if you haven't tried it."
[PJC]
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]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Knock \Knock\ (n[o^]k), v. i. [imp. & p. p. Knocked (n[o^]kt);
p. pr. & vb. n. Knocking.] [OE. knoken, AS. cnocian,
cnucian; prob. of imitative origin; cf. Sw. knacka. Cf.
Knack.]
1. To drive or be driven against something; to strike against
something; to clash; as, one heavy body knocks against
another. --Bacon.
[1913 Webster]
2. To strike or beat with something hard or heavy; to rap;
as, to knock with a club; to knock on the door.
[1913 Webster]
For harbor at a thousand doors they knocked.
--Dryden.
[1913 Webster]
Seek, and ye shall find; knock, and it shall be
opened unto you. --Matt. vii.
7.
[1913 Webster]
3. To practice evil speaking or fault-finding; to criticize
habitually or captiously. [Slang, U. S.]
[Webster 1913 Suppl.]
To knock about, to go about, taking knocks or rough usage;
to wander about; to saunter. [Colloq.] "Knocking about
town." --W. Irving.
To knock up, to fail of strength; to become wearied or worn
out, as with labor; to give out. "The horses were
beginning to knock up under the fatigue of such severe
service." --De Quincey.
To knock off, to cease, as from work; to desist.
To knock under, to yield; to submit; to acknowledge one's
self conquered; -- an expression probably borrowed from
the practice of knocking under the table with the
knuckles, when conquered. "Colonel Esmond knocked under to
his fate." --Thackeray.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Knock \Knock\, n.
1. A blow; a stroke with something hard or heavy; a jar.
[1913 Webster]
2. A stroke, as on a door for admittance; a rap. " A knock at
the door." --Longfellow.
[1913 Webster]
A loud cry or some great knock. --Holland.
[1913 Webster]
Knock off, See knock off in the vocabulary.
[PJC]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
backfire \backfire\, back fire \back fire\
1. A fire started ahead of a forest or prairie fire to burn
only against the wind, so that when the two fires meet
both must go out for lack of fuel.
[Webster 1913 Suppl.]
2.
(a) A premature explosion in the cylinder of a gas or oil
engine during the exhaust or the compression stroke,
tending to drive the piston in a direction reverse to
that in which it should travel; also called a knock
or ping.
(b) an explosion in the exhaust passages of an internal
combustion engine.
[Webster 1913 Suppl. +PJC] Backfire