💡 Detailed Explanation
"示唆" (shisa) means to hint or suggest something indirectly. The phrase "不満を示唆する" (to imply dissatisfaction) is appropriate here to describe a situation where dissatisfaction is not stated directly but can be inferred from one's attitude. Other choices: "提示" (teiji) means to present or show something clearly, which contradicts the context. "暗示" (anji) is very similar, but "示唆" often carries a stronger nuance of being inferred from objective facts or evidence. "啓示" (keiji) means a revelation, often divine, which is completely out of context.