crust crust /ˈkrʌst/

noun

1. () The outer layer of the Earth  ( Earth's crust , crust )
   the outer layer of the Earth
    The Earth's crust is the outermost layer of the planet
   The Earth's crust is the outermost layer of the planet
   
   
2. The trait of being rude and impertinent; inclined to take liberties  ( cheekiness , crust , freshness , gall , impertinence , impudence , insolence )
   the trait of being rude and impertinent; inclined to take liberties
   
3. A hard outer layer that covers something  ( crust , encrustation , incrustation )
   a hard outer layer that covers something
   

verb

1. Form a crust or form into a crust  ( crust )
   form a crust or form into a crust
    The bread crusted in the oven
   The bread crusted in the oven