Definitions

1. preposition

in opposition to; in the direction of

“The protesters marched against the government.”

2. conjunction

used to indicate a contrast or difference

“I like coffee, but she’s against it.”

3. adverb

used to indicate opposition or resistance

“The team played against all odds.”

4. noun

a person or thing that is an opponent or adversary

“The coach was concerned about the team’s opponent against the top-ranked team.”