embitter

Verb

embitter (third-person singular simple present embitters, present participle embittering, simple past and past participle embittered)

1. (archaic, transitive) To cause (something) to be or taste bitter; to bitter.

   Synonyms:

   acerbate

2. (figuratively, transitive) To cause (a positive quality such as happiness, or a thing such as an activity or one's life) to become less good or pleasurable; also, to make (a negative quality, or thing such as a disagreement) worse or more unpleasant.
   • He imbitters not a diſtaſtfull meſſage to a forrein Prince by his indiſcretion in delivering it.1642, Thomas Fuller, “The Good Herald”, in The Holy State, Cambridge, Cambridgeshire: […] Roger Daniel for John Williams, […], →OCLC, book II, paragraph 2, page 142
   • [I]t is our fond conceits, our froward humors, our perverse behaviors, which do create the trouble, which seemeth adherent to any condition, and embittereth every state; which from any slight occasion doth create vexation, and turneth every event into disaster.a. 1678 (date written), Isaac Barrow, “Sermon XXXIX. Of Contentment.”, in The Works of Dr. Isaac Barrow. […], volume III, London: A[braham] J[ohn] Valpy, […], published 1831, →OCLC, page 50
3. (figuratively, transitive) To cause (someone or their feelings) to become more angry, resentful, or unfriendly; to envenom.
   • Sometimes it [pride] ſtirreth vp men, and imboldeneth them to offer vvrongs: ſometimes imbittereth men; and maketh them vvayvvard againſt the right: […]1608, John Dod, Robert Cleaver, “Chapter XIII. [Vers[e] 10. Through mere pride doth man make contentions; but with the well aduised is wisedome.]”, in A Plaine and Familiar Exposition of the...
   • And hovv farre the like cenſurings and deſpiſings have embittered the ſpirits, and vvhetted both the tongues and pens of learned men one againſt another in our ovvne Church; […]1634 September 1 (date delivered; Gregorian calendar), Robert Saunderson [i.e., Robert Sanderson], “The Second Sermon, (Being the Fourth Ad Clerum) Preached at the Metropoliticall Visitation Holden...