What does 対 mean?

Question about Japanese
What does 対 mean?

Answer:

対（たい）　versus
対（つい）　pair

Additionally, "対" has several different meanings depends on the contexts.

[about]
この議題に対して何か意見はありませんか？
Do you have any opinion about this issue?

[anti, against]
対戦車ミサイル
Antitank missile
万人の万人に対する戦い
The war of all against all

[whereas, while]
彼が南に向かったのに対して、彼女は西へ歩いていった。
She walked toward the west, whereas he went to the south.