Nefarious and Pigheaded

Nefarious adjective - Not conforming to a high moral standard; morally unacceptable.

Pigheaded and nefarious are semantically related. In some cases you can use "Pigheaded" instead an adjective "Nefarious".

Pigheaded adjective - Sticking to an opinion, purpose, or course of action in spite of reason, arguments, or persuasion.

Nefarious and pigheaded are semantically related. Sometimes you can use "Nefarious" instead an adjective "Pigheaded".