oblique
Slanted or at an angle, not straight or level.
Oblique means slanted or at an angle, rather than straight up-and-down or perfectly horizontal. If you draw a line that tilts diagonally across your paper, you've drawn an oblique line. When sunlight streams through your window in the late afternoon, it hits the floor at an oblique angle, creating long shadows.
The word also describes something indirect or not straightforward. An oblique comment hints at something without saying it directly. If your friend asks how their haircut looks and you respond, “Well, it's certainly different,” you've given an oblique answer, one that avoids directly stating your opinion. Teachers sometimes make oblique references to upcoming tests without announcing them plainly.
In geometry, an oblique triangle is one that doesn't have a right angle (all its angles are either acute or obtuse). An oblique muscle in your body runs at an angle rather than straight up and down.
When someone approaches a problem from an oblique angle, they're tackling it indirectly or from an unexpected direction. This can sometimes be the most creative way to solve a difficult puzzle or understand a complicated idea.