Bullheaded and Spur-of-the-moment

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

Spur-of-the-moment and bullheaded are semantically related. In some cases you can use "Spur-of-the-moment" instead an adjective "Bullheaded".

Spur-of-the-moment adjective - Made or done without previous thought or preparation.

Bullheaded and spur-of-the-moment are semantically related. Sometimes you can use "Bullheaded" instead an adjective phrase "Spur-of-the-moment".