Is the word optimistic a synonym for criticize?

No, "optimistic" is not a synonym for "criticize." They are antonyms, meaning they have opposite meanings.

* Optimistic means having or showing a positive outlook or belief in a favorable outcome.

* Criticize means to express disapproval of someone or something.

Here are some examples to illustrate the difference:

* Optimistic: "She was optimistic about the future of the company."

* Criticize: "The reviewer criticized the movie's plot."