The word 诉苦 is formed by combining the character 诉, meaning "to tell" or "to complain", with the character 苦, meaning "bitterness" or "hardship". Together, they create a compound word where 诉 acts as a verb indicating the action of expressing, and 苦 serves as the object denoting the content being expressed, resulting in the meaning "to pour out one's grievances" or "to complain about suffering".