Odd One Out — From Whim, Quirk, Caprice, and Foible, identify the word that does not share the meaning of a sudden notion or unpredictable fancy.

Introduction / Context:
Vocabulary classification hinges on synonymy. Three options are near-synonyms, and one differs in meaning.

Given Data / Assumptions:

• Whim, Caprice: a sudden fancy or passing notion.
• Quirk: often a peculiar trait or idiosyncrasy; used loosely near the same idea of unpredictability.
• Foible: a minor weakness or flaw in character.

Concept / Approach:
Group words by shared core meaning: sudden notion or unpredictable fancy vs personal weakness.

Step-by-Step Solution:
Whim and Caprice align strongly as synonyms.Quirk, while broader, commonly overlaps with unpredictable peculiarities.Foible specifically indicates a small character weakness, not a sudden fancy.

Verification / Alternative check:
Substitute each into the phrase “a sudden _____ overtook her”; Foible fails the sense check.

Why Other Options Are Wrong:

• Whim: synonym of caprice.
• Quirk: acceptable near-synonym in many contexts here.
• Caprice: the core sense itself.

Common Pitfalls:
Treating Quirk as strictly unrelated; in usage it can convey unpredictable oddness.

Final Answer:
Foible