Analogy (adjective–noun association): Match the state of motion or rest with the appropriate natural medium. Given pair: Flow : River :: Stagnant : ? Choose the correct term to complete the analogy.

Given data

• Pair: Flow : River :: Stagnant : ?
• "Flow" commonly characterizes a river (flowing river).

Concept / Approach We need a noun that is naturally described as "stagnant." The standard collocation is "stagnant water."

Step-by-step reasoning "Flow" ↔ "River" (typical property). "Stagnant" ↔ Water (typical property).

Eliminate distractors Air can be still but "stagnant air" is less canonical in such basic analogies; Wind implies movement (opposite of stagnant); Cloud is not idiomatically called stagnant.

Final Answer Water