Select the most appropriate ANTONYM of the given word. Delineate

Concept: An antonym is a word carrying the opposite meaning of a given word. To find it, first fix the exact core sense of the given word — not just its general subject area — then look for the option whose meaning is the direct reverse of that specific sense.

Application: "Delineate" is a verb meaning to describe, portray, sketch, or outline something precisely and clearly, as in delineating a boundary or a plan. The direct opposite of this sense is a word meaning to make something unclear or to prevent it from being seen or understood clearly. Among the options, "Obscure" carries exactly this reversed meaning — as a verb, it means to make something unclear, indistinct, or hard to see or understand, or to hide it from view — making it the antonym of "delineate".

Contrast: the remaining three options belong to different areas of meaning altogether and do not reverse the sense of describing something precisely —

• "Apathetic" concerns emotional indifference — a lack of interest, concern, or enthusiasm — not the clarity of a description.

• "Deceptive" concerns creating a false or misleading impression, often with intent to trick — not the presence or absence of a clear outline.

• "Arduous" concerns the effort a task demands — being difficult, strenuous, and tiring — not how clearly something is depicted.

None of these three reverses the sense of "delineate" the way "Obscure" — the direct opposite of describing something clearly — does.