Autonomy refers to respecting an individual's right to make their own decisions about their healthcare, even if those decisions go against medical advice. In this scenario, the nurse is displaying the ethical principle of autonomy by supporting the client's refusal of medications. By respecting the client's decision, the nurse upholds their right to self-determination, even if it means disagreeing with the prescribed treatment.

Justice is the principle of fairness and equality in the distribution of healthcare resources and treatments. It does not directly apply in this situation where the client's autonomy is the primary concern.

Veracity is the principle of honesty and truthfulness in communication with patients. It does not directly apply in this situation where the client's autonomy is at the forefront of the decision-making process.

Beneficence refers to the principle of promoting the well-being and best interests of the patient. In this case, the nurse is respecting the client's autonomy, which might conflict with the principle of beneficence if the nurse believes the medication is in the client's best interest. However, autonomy takes precedence in this situation.