Source: The Great Interpretation of Dreams (Ibn Sirin)
A monkey in a dream is a poor, deprived man whose blessing has been stripped away. He indicates a cunning, deceitful man. Whoever turns into a monkey has committed a major sin.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
A monkey indicates a Jewish man or a cursed enemy. Arguing with it indicates illness.
Source: Signs in the Science of Expressions (Ibn Shaheen)
A monkey is interpreted as a cursed enemy. Its bite indicates a dispute or illness.