sincereadjective · Level 3 SAT1characterized by a firm and humorless belief in the validity of your opinionsHis sincere belief in the cause made him willing to sacrifice personal comfort and ambition.ModuleLevel 3Registerliterary, toneCollectionCollection 027SAT Complete planAlso in Collection 027toadyish, unrepentant, loathsome, pachydermatous, remorseful, ruthful, unsparing, minacious and 1 more