Classification – Odd one out (word sense): Select the word unlike the others by meaning: Solid, Plump, Fathom, Thick.

Introduction / Context:
Lexical classification often separates adjectives of similar semantics from a member with a different part of speech or core sense. Three items are descriptive adjectives of bulk/consistency; one is primarily a verb (and also a unit of length), making it semantically and grammatically distinct.

Given Data / Assumptions:

• Solid: adjective relating to firmness/density/consistency.
• Plump: adjective describing roundness/fullness.
• Fathom: chiefly a verb meaning “to understand deeply”; also a nautical length unit (~6 feet).
• Thick: adjective indicating high density or dimension across a small axis.

Concept / Approach:
Identify part-of-speech and core semantic field. Three words are adjectives describing physical build/consistency; “Fathom” stands apart as a verb/noun unit, not describing thickness/bulk.

Step-by-Step Solution:
Check grammatical category: Solid/Plump/Thick → adjectives; Fathom → verb/noun.Check semantics: Solid/Plump/Thick → corporeal attributes; Fathom → cognition or measurement.

Verification / Alternative check:
Substitute in a sentence about physical density: “The soup is very ____.” Solid/Thick/Plump can fit; Fathom does not, unless rephrased into the verb sense, confirming the mismatch.

Why Other Options Are Wrong:

• Solid, Plump, Thick: aligned adjectives of physical description.

Common Pitfalls:
Confusing “solid” as a noun or “fathom” as a rare adjective; the dominant, common usages separate them clearly.

Final Answer:
Fathom