prep.1. In a direction or course opposite to: row against the current.
2. So as to come into forcible contact with: waves dashing against the shore.
3. In contact with so as to rest or press on: leaned against the tree.
4. In hostile opposition or resistance to: struggle against fate.
5. Contrary to; opposed to: against my better judgment.
6. In competition with: raced against the record holder.
7. In contrast or comparison with the setting or background of: dark colors against a fair skin.
8. In preparation for; in anticipation of: food stored against winter.
9. As a defense or safeguard from: protection against the cold.
10. To the account or debt of: drew a check against my bank balance.
11. Directly opposite to; facing.