n. 1. That which knocks one down; something that overpowers or overwhelms, as strong liquor; specif., a kind of ale or beer that is very strong. [ Slang. ] [ Webster 1913 Suppl. ]
2. A knocking down; a felling by a knock, as of a combatant, or of an animal; a blow that overwhelms; also, a fist fight. [ Webster 1913 Suppl. ]
3. Something that knocks down, or takes apart, for packing or removal, as a piece of furniture; also, state of being knocked down, or taken apart. [ Webster 1913 Suppl. ]
a. 1. Of force sufficient to fell or completely overthrow; as, a knockdown blow; a knockdown argument.. [ Webster 1913 Suppl. ]
2. Designating a rivet end to be formed into a head by upsetting in fastening. [ Webster 1913 Suppl. ]
3. Of or pertaining to the act of knocking down at an auction; specif., designating the price below which an article will not be disposed by the auctioneer. [ Webster 1913 Suppl. ]
4. Made or constructed so as to be capable of being knocked down or taken apart, as for transportation. [ Webster 1913 Suppl. ]
adj. marked by extreme violence; -- of fights; also used metaphorically of fierce contests; as, a knock-down-and-drag-out fight; a knockdown-dragout competition for the browser market. Syn. -- ferocious, fierce, knockdown-dragout, tearing. [ WordNet 1.5 +PJC ]