To slant means to be at an angle instead of straight up and down.
A slant can make people think of something not being quite right or of something being a little bit different.
Examples:
The roof slants down on one side.
The tree grows at a slant.
The bookshelf is slanted against the wall.
The cat likes to sit on a slant.
The tower leans at a slant.
The slide is slanted, so it's faster to go down.