The difference between Oblique and Roman

Oblique as an adjective:

Not erect or perpendicular; neither parallel to, nor at right angles from, the base; slanting; inclined.

Oblique as an adjective:

Not straightforward; indirect; obscure; hence, disingenuous; underhand; perverse; sinister.

Oblique as an adjective:

Not direct in descent; not following the line of father and son; collateral.

Oblique as an adjective (botany):

Of leaves, having the base of the blade asymmetrical, with one side lower than the other.

Oblique as an adjective (botany):

Of branches or roots, growing at an angle that is neither vertical nor horizontal.

Oblique as an adjective (grammar):

Pertaining to the oblique case (non-nominative).

Oblique as an adjective (grammar):

Of speech or narration, indirect, employing the actual words of the speaker, but as related by a third person, having the first person in pronoun and verb converted into the third person, adverbs of present time into the past, etc.

Oblique as an adjective (music):

Employing oblique motion, motion or progression in which one part (voice) stays on the same note while another ascends or descends.

Oblique as a noun (geometry):

An oblique line.

Oblique as a noun:

⟨/⟩.

Oblique as a noun (grammar):

The oblique case.

Oblique as a verb (intransitive):

To deviate from a perpendicular line; to move in an oblique direction.

Oblique as a verb (military):

To march in a direction oblique to the line of the column or platoon; — formerly accomplished by oblique steps, now by direct steps, the men half-facing either to the right or left.

Oblique as a verb (transitive, computing):

To slant (text, etc.) at an angle.

Roman as an adjective (of type, typography):

Upright, as opposed to italic.

Roman as an adjective (of text, computing):

Of or related to the Latin alphabet.