Against can mean:

• in an opposite direction - walking against the wind
• in front, touching, or resting - The man was standing against the tree.
• in opposition - against all odds
• in competition - The boy played chess against his father.
• touching with strong force - Ocean waves crash against the swimmer.
• as a protection from - She used an umbrella against the strong rain."

Other meanings

• Against was the seventh album by Brazilian thrash metal band Sepultura. It came out in 1998 from Roadrunner Records.