A final refusal is an Office Action sent to the applicant after a response to a non-final action has been received by the Office and reviewed by the examining attorney. In the final refusal the examining attorneys informs the applicant that either the arguments presented in their response did not affect the grounds for refusing registration, or that the information submitted did not satisfy the requirements set forth in the original office action.
There are two ways to respond to a final Office action: compliance with the requirements, or an appeal to the Trademark Trial and Appeal Board.