Islamic Interpretation of Dreams (Ibn-i Sirin):

In a dream, eavesdropping means backbiting and lies. Perhaps the one who is eavesdropping on others may become despised by the ruler or his superior. On the other hand, if one sees himself in a dream inadvertently listening to a conversation, and if the one seeing the dream is a merchant, it means that he will resign from the leadership of his business, and ifhe is a ruler, it means that he will be removed from his post.

If one sees himself harkening to another person in a dream, it means that he desires to defame him or expose his pitfalls.

If one sees himself listening to some talks of which he follows the better avenues in the dream, it means that he will receive glad tidings.

If one sees himself listening to admonition but ignoring it in a dream, it means that he lies as a habit.