Definition
'Pertinacious' describes someone who is stubbornly persistent or holding firmly to an opinion or course of action. It implies a strong-willed determination that can be admirable, but also annoying if the person is wrong. Think of a lawyer relentlessly questioning a witness, even when they are reluctant to answer. It suggests a refusal to be swayed or deterred, often in the face of opposition. A pertinacious person is not easily discouraged.