To be of no importance; to mean nothing to someone.
To be a matter about which one feels no concern or interest.
2.
SpainLatin Americainformalhumorous
To describe something as trivial or insignificant in a jocular or dismissive way.
Examples:
ES: Oye René, queria decirte que he oido tu discurso y estoy totalmente de acuerdo porque a nosotros de las audiencias no nos tiene que importar un pepino!
EN: I heard your speech, René, and I totally agree, we shouldn't give a crap about ratings!
ES: - Pero ¡cómo le va a importar un pepino, si se trata de su hijo!
EN: - How can you not give a damn if it's your son!