Most pucker-inducing

TARTEST

"Hint: Think of the superlative form of a word that describes a sharp, sour flavor. (This hint guides the solver toward the idea of a superlative adjective related to taste, specifically one that causes puckering, without directly giving away "tartest.")"

Clue: "Most pucker-inducing" Answer: "TARTEST" Explanation: The word "pucker-inducing" suggests something that causes a sour or bitter taste, often associated with the word "tart." The suffix "-est" is the superlative form, indicating the highest degree of that quality.