Related to antiparticles or antimatter.
Against, hostile to.
Physically opposite: applied to mountain ranges.
Opposite of, reverse.
Indicating that a game's conventional victory conditions have been reversed: misère.
Counteracting, neutralizing.
Contrasting with the norm.
That reacts with immunoglobins found in the specified animal.
Being, of having an opponent; not unopposed.
Opposite.
Acting in opposition; opposing.