fastness fastness /ˈfæstnəs/

noun

1. A strongly fortified defensive structure  ( fastness , stronghold )
   a strongly fortified defensive structure
   
   
2. The quality of being fixed in place as by some firm attachment  ( fastness , fixedness , fixity , fixture , secureness )
   the quality of being fixed in place as by some firm attachment
   
3. A rate (usually rapid) at which something happens  ( fastness , swiftness , speed )
   a rate (usually rapid) at which something happens
    The project advanced with gratifying speed
   the project advanced with gratifying speed