Terquedad vs. obstinación vs. tozudez vs. testarudez
The Spanish language offers several ways to describe the act of being immovable, but they carry different nuances. While terquedad is the most general term for stubbornness, obstinación implies a more formal or intense fixation on a goal. Meanwhile, testarudez and tozudez describe personality traits, with the former referring to being hard-headed and the latter often implying an illogical or mule-headed refusal to reason.
Terquedad
B2This is the most standard and common term to describe general stubbornness. Terquedad refers to a person's refusal to change their opinion, attitude, or course of action, often appearing unreasonable to others.
Su terquedad le causó muchos problemas con su jefe.
(His stubbornness caused him many problems with his boss.)
No entiendo tu terquedad en no querer usar el mapa.
(I do not understand your stubbornness in not wanting to use the map.)
Debido a su terquedad, perdimos el tren por no preguntar la hora.
(Due to his stubbornness, we missed the train by not asking for the time.)
Obstinación
C1This word is more formal and refers to a persistent tenacity in maintaining an idea or purpose. While obstinación is usually negative (blind fixation), it can sometimes hint at a strong will or perseverance in achieving a difficult goal.
La obstinación del científico le llevó finalmente al descubrimiento.
(The scientist's persistence finally led him to the discovery.)
Su obstinación por comprar esa casa es preocupante.
(His obstinacy regarding buying that house is worrying.)
Luchó con gran obstinación contra la enfermedad.
(He fought with great tenacity against the illness.)
Tozudez
C2Tozudez conveys the image of being mule-headed. It often implies a lack of logic or intelligence in the stubbornness. A person displaying tozudez simply digs their heels in and refuses to move or understand valid arguments.
Es imposible debatir con él, su tozudez es infinita.
(It is impossible to debate with him, his pig-headedness is infinite.)
La mula se detuvo con una tozudez que nos desesperó.
(The mule stopped with a stubbornness that exasperated us.)
Deja la tozudez y admite que te has equivocado.
(Stop the pig-headedness and admit that you were wrong.)
Testarudez
C1Derived from the word for head, testarudez describes someone who is hard-headed. It is very similar to terquedad but focuses more on the personality trait of being firm and unyielding, often driven by pride or habit.
Su testarudez le impidió aceptar la ayuda de sus amigos.
(His hard-headedness prevented him from accepting help from his friends.)
Es conocido en el pueblo por su gran testarudez.
(He is known in the town for his great stubbornness.)
Solo la testarudez le hizo seguir adelante cuando todos se rindieron.
(Only his doggedness made him keep going when everyone else gave up.)
Summary
In short, use terquedad for general situations where someone refuses to listen. Use obstinación when the stubbornness is focused on a specific goal or idea, often with intensity. Use tozudez when the stubbornness seems illogical, annoying, or brute (like a mule). Finally, use testarudez to describe a hard-headed personality trait rooted in firm conviction or pride.