antithesis
1. [ noun ] exact opposite
Examples:

"his theory is the antithesis of mine"

Related terms: opposition
2. [ noun ] (rhetoric) the juxtaposition of contrasting words or ideas to give a feeling of balance
Related terms: rhetorical_device
Similar spelling:   antitrades
  antithetic
  antithyroid
  and_others
  antitype
  antithetical
  antitrust
  antitrade