in opposition to

: a configuration (see configuration 1b) in which one celestial (see ¹celestial 2) body is opposite another (such as the sun) in the sky or in which the elongation (see elongation 1) is near or equal to 180 degrees

: the relation between two propositions having the same subject and predicate but differing in quantity or quality or both

: an act of setting opposite or over against : the condition of being so set