What does 逆効果 mean?
逆効果 is a Japanese noun meaning “opposite effect” in English. It is written as 逆効果 in kanji, ぎゃくこうか in hiragana, and gyakukouka in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
そんなことをしたら逆効果になる。
If you do that, it will only bring about a contrary effect.