dignarse

A reflexive verb meaning to deign, or lower oneself, to do something — almost always used with a note of resentment or irony about someone finally doing what they should have done all along: ni siquiera se dignó a contestar.

• Ni siquiera se dignó a saludarme. — He didn't even deign to say hello to me.
• Después de horas de espera, el jefe se dignó a recibirnos. — After hours of waiting, the boss finally condescended to see us.
• No se dignaron a explicar por qué cancelaron el vuelo. — They didn't bother to explain why they canceled the flight.

Dropping the reflexive pronoun or the preposition a — the verb needs dignarse a + infinitive (se dignó a responder), not just dignar, which isn't how it's used in modern Spanish.