1bit·ter 
/ˈbɪtɚ/ adjective
/ˈbɪtɚ/ adjective [more bitter; most bitter] ◊The form bitterer is almost never used to mean “more bitter,” but the form bitterest is commonly used to mean “most bitter.” 1 : having a strong and often unpleasant flavor that is the opposite of sweet
▪ Cocoa beans have a bitter flavor. ▪ The medicine had a bitter aftertaste. 2 : causing painful emotions
▪ bitter disappointments ▪ a bitter defeat : felt or experienced in a strong and unpleasant way ▪ We were struck by the bitter irony of the situation. ◊A bitter pill or a bitter pill to swallow is something that is difficult or painful to accept.
▪ The defeat was a bitter pill for the team to swallow. 3 : angry and unhappy because of unfair treatment
▪ His betrayal had made her bitter. ▪ She was still bitter toward her ex-husband. ▪ He's the bitterest man I know. 4 : feeling or showing a lot of hatred or anger
▪ bitter enemies ▪ a bitter argument ▪ a bitter reply 5 : very cold
▪ a bitter wind ▪ bitter cold
▪ Cocoa beans have a bitter flavor. ▪ The medicine had a bitter aftertaste.
▪ bitter disappointments ▪ a bitter defeat : felt or experienced in a strong and unpleasant way ▪ We were struck by the bitter irony of the situation. ◊A bitter pill or a bitter pill to swallow is something that is difficult or painful to accept.
▪ The defeat was a bitter pill for the team to swallow.
▪ His betrayal had made her bitter. ▪ She was still bitter toward her ex-husband. ▪ He's the bitterest man I know.
▪ bitter enemies ▪ a bitter argument ▪ a bitter reply
▪ a bitter wind ▪ bitter cold
to/until the bitter end
: until the end of something that may be very bad, unpleasant, etc.
▪ I knew she would stand by me to the bitter end. ▪ He vowed that he would keep fighting until the bitter end.
▪ I knew she would stand by me to the bitter end. ▪ He vowed that he would keep fighting until the bitter end.
— bit·ter·ly adverb
▪ We were bitterly disappointed. ▪ He complained bitterly about the crowds. ▪ bitterly cold
▪ We were bitterly disappointed. ▪ He complained bitterly about the crowds. ▪ bitterly cold
— bit·ter·ness noun [noncount]
