Verb

refuse to accept or be associated with. Reject.

source: dictionary.com

word is found in chapter 14 “Quicksand”

”In America Negroes sometimes talked loudly of this, but in their hearts they repudiated it.”

here Helga Crane is justifying her new life was now pleasing to her as it satisfied her “self-importance”, but to her the Negroes embrace the idea of being themselves on the surface not within their hearts as she believed they wanted to be more like the “whites” rather than black.