noun
plural -ters
[noncount] :a solid yellow substance made from milk or cream that is spread on food or used in cooking
[count, noncount] :a food made from cooked fruit or roasted nuts that have been ground up
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
verb
-ters; -tered; -tering
[+ obj] :to spread or put butter on (something)
butter up
[phrasal verb]
butter up (someone) or butter (someone) up informal :to treat (someone) very well or kindly in order to get something
know which side your bread is buttered on
US