申诉 (shēn sù) is a formal verb meaning 'to appeal' — specifically, to formally challenge or request a review of an official decision, ruling, or administrative action. The first character 申 (shēn) conveys 'to state clearly', 'to declare', or 'to explain thoroughly', while 诉 (sù) means 'to sue', 'to accuse', or 'to lodge a complaint'. Together, they emphasize a structured, official act of voicing dissatisfaction with the aim of redress, not casual complaining. It’s commonly used in legal, governmental, educational, and workplace contexts — for example, appealing a disciplinary penalty, contesting a medical insurance denial, or challenging a school admission decision.

Unlike everyday words like 抱怨 (bào yuàn, 'to complain') or 反对 (fǎn duì, 'to oppose'), 申诉 carries procedural weight and implies adherence to formal channels and deadlines. It often requires written documentation and submission to a specific authority. The noun form refers to the appeal itself (e.g., 提交申诉, 'submit an appeal'), and it’s typically followed by objects like 决定 (jué dìng, 'decision'), 处分 (chǔ fèn, 'disciplinary action'), or 判决 (pàn jué, 'judgment').