Actually, neither.
The opposite of peace is not-peace. War is one type of not-peace. There are also contraries and contradictories, like “both peace and not-peace” and “neither peace nor not-peace.” If these semiotics were not enough, ordinary language has its versions. Other people think in threes or more, e.g., Virginia Woolf talks about Peace, Love and Hate as the biggies.
Once you’ve got more than a dualism, the contradistinctions go any which way. If Peace is the freedom from extreme love and hate, Woolf’s threesome become Love, Hate and Freedom from extreme versions of both. And by talking about Peace being “a freedom from,” you stumble into “freedom to,” as in: Why not freedom-to as its own kind of Peace?
–For my part, a better question is: What is neither peace nor not-peace? One answer would be a world so complex that the determination of what is “peace” versus “not-peace” is not possible. How so? Because right now nothing has been reconciled, yet.
It’s as if when reading World War II entries in John Colville’s Downing Street Diaries, you were also experiencing real time today. It would be to read Hardy’s 1912 poem, “Convergence of the Twain,” as if it were still part of the news about the Titanic sinking the month before.