Munjuk is a word of Malay origin which means pretentious or deceitful. Though it is not commonly used in English, there are many synonyms that can convey similar meanings like insincere, fake, phony, artificial, fraudulent, deceptive, spurious, counterfeit, hypocritical, and ostentatious. These words describe someone or something that is not genuine, sincere or honest. They are often used to describe behavior or language that is meant to impress or sway others but lacks authenticity. Choosing the right synonym will depend on the context and intended meaning, but each of these words can be used to describe someone or something that is not quite what it seems.