noun which may take the genitive case particle 'no', na-adjective, noun
exactly opposite; completely contrary
Emphasizes a total, diametrical opposition. Often used in the pattern ～と正反対だ or as a な-adjective modifying a noun.
彼の意見は私の意見と正反対だ。
His opinion is exactly the opposite of mine.
兄は私と正反対の性
My older brother has a personality completely opposite to mine.