Nebulous : Form — Choose the pair showing an adjective that signals “lack of the named quality/attribute” for the noun.

Introduction / Context:
“Nebulous” means vague, indistinct, or lacking definite form; thus the pair “nebulous : form” signals absence/weakness of the noun’s defining attribute. We need a similar pattern: an adjective that denotes lack or deficiency of the noun’s named quality.

Given Data / Assumptions:

• Nebulous ↔ lacking clear form.
• We seek a comparable adjective–noun mismatch indicating absence.

Concept / Approach:
“Insipid” means lacking flavor or zest; pairing it with “taste” reproduces the structure: adjective indicates the absence of the noun’s salient attribute. This mirrors “nebulous : form.”

Step-by-Step Solution:
Identify relation: adjective denotes deficiency of the noun’s attribute.Select “Insipid : Taste”.

Verification / Alternative check:
Dictionaries define insipid as “lacking flavor, bland.” The mapping holds directly.

Why Other Options Are Wrong:

• Insincere : Misanthrope — mismatched parts; misanthrope is a person, not a quality.
• Benevolent : Excellence — benevolent is kindness; “excellence” is a quality, mismatched logic.
• Composed : Innocence — unrelated traits.
• Opaque : Transparency — closer as opposites but noun should be “transparency” abstract; still not the precise deficiency relation akin to “insipid : taste.”

Common Pitfalls:
Choosing any antonym pair without preserving adjective–noun deficiency structure.

Final Answer:
Insipid : Taste