To "tamper" means to interfere with something in a way that alters or damages it. This action often involves unauthorized changes or manipulations, which can lead to negative consequences. For example, tampering with evidence in a criminal investigation can obstruct justice and affect the outcome of a case. Tampering can occur in various contexts, such as in food safety, where someone might alter expiration dates, or in technology, where software can be modified to bypass security measures. Such actions are typically illegal and can result in serious penalties for those involved.