Rendering someone unconscious. / Amazing; gorgeous; beautiful. / (genetics) Designating an organism in which a particular gene has been removed or deactivated. / Causing elimination from a competition.

An abrupt rapping sound, as from an impact of a hard object against wood. / A sharp impact. / (figuratively) A criticism. / (figuratively) A blow or setback.

(transitive, dated) To strike for admittance; to rap upon, as a door. / (transitive, colloquial) To criticize verbally; to denigrate; to undervalue.

A device, usually hinged with a striking plate, used for knocking on a door. / A person who knocks. / A critic; one who disparages. / (informal, derogatory) A person who knocks (denigrates) something.

An informal game involving physical activity, usually football.

(intransitive, often followed by with) To spend time companionably; to hang around. / (transitive) To engage in a relaxing activity in; to hang around in.

A looping of a piece of string or of any other long, flexible material that cannot be untangled without passing one or both ends of the material through its loops. / (of hair, etc) A tangled clump.

(transitive) To form into a knot; to tie with a knot or knots. / (transitive) To form wrinkles in the forehead, as a sign of concentration, concern, surprise, etc. / To unite closely; to knit together.

One of a variety of shore birds; the red-breasted sandpiper (variously Calidris canutus or Tringa canutus).

(imperative, slang) A mildly offensive expression of refusal.