Is the word bereft used correctly?
The bereft husband felt depressed after losing his wife.

Yes

Explanation:

Bereft can mean not having something or feeling great loss, and so if he lost his wife he will be feeling a great loss

the sentence does not violate the phrase structure second rule (introduced by noam chomsky) because noun phrases consist of a determiner such as a, the or every, and a noun. in the sentence, the noun phrase the cake includes a determiner (the) and a noun (cake).

on the other hand, the first rule indicates that a sentence encloses a noun phrase, followed by a verb phrase. the example sentence can be analysed as follows:

john (n) + ate (v) + the (det) + cake (n).

the answer can be "credo" it means to believe = the word credo means "an official statement of beliefs"