How to say "against" in Japanese

• 対たいJLPT N3approx.Common
  nounCovers 'against' only in the versus sense: opposing sides in a game, debate, or comparison — essentially 'vs.'. For opposition directed at something, this is not the word; use に対して.
  今日きょう早稲田わせだ対たい慶応けいおうの試合しあいがある。↗

  There is going to be a game between Waseda and Keio today.
• に対してにたいしてCommon
  expression'Against' here is opposition directed at a target — feelings, actions, or arguments aimed at someone or something. The word otherwise means 'towards' or 'in contrast with', marking the target of an action or attitude.
  私のおいは卵たまごに対たいしてアレルギー体質たいしつだ。↗

  My nephew is allergic to eggs.

Choose 対 for the versus sense of 'against' — opposing sides in a match or comparison — and 「に対して」 when something is directed at a target, its 'towards' or 'in contrast with' senses.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 対たいversus
• に対してにたいしてtowards
• に反してにはんしてagainst
• に対しにたいしtowards