A "lame excuse" refers to a justification or reason that is weak, unconvincing, or inadequate. People often use lame excuses to avoid responsibility or to explain why they failed to meet an obligation. These excuses typically lack credibility and can be easily challenged or dismissed by others. Common examples of lame excuses include saying, "I forgot," or "My dog ate my homework." Such explanations are often seen as insincere or trivial, leading to frustration among those who expect accountability. In various contexts, including work or school, lame excuses can undermine trust and credibility.