All 3 Uses of

denounce
in
The Souls of Black Folk

To praise this intricate whirl of thought and prejudice is nonsense; to inveigh indiscriminately against "the South" is unjust; but to use the same breath in praising Governor Aycock, exposing Senator Morgan, arguing with Mr. Thomas Nelson Page, and denouncing Senator Ben Tillman, is not only sane, but the imperative duty of thinking black men.†
Chpt 3 *

denouncing = strongly criticizing or accusing publicly OR (more rarely) informing against someone

What wonder that every tendency is to excess,—radical complaint, radical remedies, bitter denunciation or angry silence.†
Chpt 10

denunciation = strong criticism or public accusation OR (more rarely) reporting someone to the authorities

John never knew clearly what the old man said; he only felt himself held up to scorn and scathing denunciation for trampling on the true Religion, and he realized with amazement that all unknowingly he had put rough, rude hands on something this little world held sacred.†
Chpt 13

Definitions:

(1) (denounce)
to strongly criticize or accuse publicly

or more rarely: to inform against someone (turn someone into the authorities)
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Much more rarely, denounce can indicate the termination of a treaty or other formal agreement.