Origin: French suffix -ique
Oblique has 7 different meanings across 2 categories:
any grammatical case other than the nominative
"In ancient Greek grammar, every noun except the subject appears in an oblique case such as accusative or genitive."
a diagonally arranged abdominal muscle on either side of the torso
"The surgeon repaired his torn obliques after the accident."
An oblique line.
"The architect drew an oblique line across the blueprint to indicate a diagonal support beam."
To deviate from a perpendicular line; to become askew;
"The leaning tower of Pisa is so oblique that its shadow does not fall directly beneath it at noon."
In plain English: To oblique something is to move away from it indirectly instead of going straight toward it.
"She obliqued her head to avoid looking directly at him."
slanting or inclined in direction or course or position--neither parallel nor perpendicular nor right-angled
"the oblique rays of the winter sun"
"acute and obtuse angles are oblique angles"
"the axis of an oblique cone is not perpendicular to its base"
Not erect or perpendicular; not parallel to, or at right angles from, the base
"The oblique roof slanted sharply away from the vertical walls of the barn."
In plain English: Oblique means not direct, straight on, or head-on but instead coming from an angle.
"The oblique angle of the sun made my shadows stretch across the lawn."
Usage: Use oblique primarily in geometry and photography to describe lines that are slanted rather than straight up-and-down. Avoid using it as a synonym for "indirect" when referring to speech, which is the more common everyday meaning of the word today.
The word comes from the Middle French oblíque, which was borrowed from the Latin obliquus. Originally meaning "slanting" or "sideways," it traveled into English to describe anything that is not direct.