Select the word or phrase which best expresses the meaning of the given word.

Agitate means to cause anxiety, disquiet, or physical disturbance—directly synonymous with 'disturb.' Soothe is its antonym (opposite), refresh means to renew, and suppress means to restrain or inhibit, none of which capture the core meaning of agitate.

Step-by-step Derivation:
Analyze the definition of 'agitate': (1) to make anxious or nervous; (2) to stir or shake vigorously. The closest synonym from the options is 'disturb,' which encompasses both the emotional (causing unease) and physical (causing disruption) senses of agitate. Option A (Soothe) is antonymous. Option B (Refresh) is unrelated. Option D (Suppress) implies containment, not disturbance.