You could read a synopsis of both and understand everything enough. I'd argue NOT playing Ground Zeroes would actually benefit MGS V as it kind of screams some of the plot twists if you pay attention.
Bare bones is this
Peace Walker = Big Boss fights a rogue CIA group and stops a nuclear apocalypse, has to deal with his trauma from MGS 3 in the process. Accepts his role as Big Boss, is then attacked by a double agent who works for Major Zero, and formally declares their current mother base Outer Heaven as a result.
Ground Zero = Big Boss has to infiltrate Guantanamo Bay to rescue a child soldier who worked with him as well as the double agent from the end of Peace Walker in order to keep them from leaking details to Major Zero. This turns out to be a diversion to get him away from Outer Heaven, and Major Zeroes strike force XOF infiltrates and destroys the base. During his escape, Big Boss is involved in a helicopter crash and falls into a coma. ---