embittered

UK: /ɪmˈbɪtə^rd/

WordReference Random House Learner's Dictionary of American English © 2025

em•bit•ter /ɛmˈbɪtɚ/   v. [~ + object]

1. to make (someone) bitter and angry;
   cause (someone) to feel bitterness:
   Being fired from his job without good reasons embittered him.

WordReference Random House Unabridged Dictionary of American English © 2025

em•bit•ter  (em bit′ər), v.t. 

1. to make bitter;
   cause to feel bitterness:
   Failure has embittered him.
2. to make bitter or more bitter in taste.

Also, imbitter. 

• em-¹ + bitter 1595–1605

em•bit′ter•er, n. 
em•bit′ter•ment, n. 
Synonyms

• 1. . sour, rankle, envenom.

Collins Concise English Dictionary © HarperCollins Publishers::

embitter / ɪmˈbɪtə/ verb (transitive)

1. to make (a person) resentful or bitter
2. to aggravate (an already hostile feeling, difficult situation, etc)

emˈbittered adjective

emˈbitterment noun