butter
but·ter
I
 /ˈbʌtɚ/  noun  ,  pl   -ters
  1 [  noncount  ] : a solid yellow substance made from milk or cream that is spread on food or used in cooking
   bread and butter
   Would you like some butter for your potato?
   Sauté the onions in melted butter.
  — see also bread and butter
  2 [  count  ,  noncount  ] : a food made from cooked fruit or roasted nuts that have been ground up
   apple butter
  — see also peanut butter
  butter wouldn't melt in someone's mouth
    chiefly Brit   — used to say that a person who appears to be innocent, sincere, or kind is really not
  like a (hot) knife through butter — see knife, 1
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II
  verb  , -ters, -tered, -ter·ing [  + obj  ]
  : to spread or put butter on (something)
   butter a piece of bread
   buttered toast
  butter up [  phrasal verb  ]
   butter up (someone) or butter (someone) up informal : to treat (someone) very well or kindly in order to get something
    He's busy buttering up potential clients.
  know which side your bread is buttered on — see bread, 1