set (something or someone) against

phrasal verb

set (something or someone) against; setting (something or someone) against; sets (something or someone) against

1

: to put (something) in a place or position so that it is touching (something else)

He set the ladder against the wall.

2

: to cause the action of (a film, story, etc.) to happen in (a certain place or during a certain time)

—often used as be set against

The story is set against (the backdrop of) the Second World War.

3

: to compare (something) to (something else)

Let's set the advantages against the disadvantages.

—often used as (be) set against

The fines were small when set against the company's huge annual profits.

4

British : to list (something) as an expense in order to reduce (income for which tax is due)

You can set your mortgage payments against your rental income.

5

: to cause (someone) to disagree with or oppose (someone)

The incident set brother against brother.