knockdown
knock‧down1 /ˈnɒkdaʊn $ ˈnɑːk-/ 
adjective [only before noun] informal
a knockdown price is very cheap
knockdown2 noun [countable]
when a boxer falls down when he is hit
| I |
adjective [only before noun] informala knockdown price is very cheap
| II |
noun [countable]when a boxer falls down when he is hit