The answer is Urdu.
Hindi, Sindhi, Oriya, and Gujarati are all Indo-Aryan languages, while Urdu is a member of the Indo-Iranian language family. Indo-Aryan languages are a group of languages that are descended from Sanskrit, the classical language of India. Indo-Iranian languages are a group of languages that are descended from Proto-Indo-Iranian, the ancestor of both Indo-Aryan and Iranian languages.
Hindi is the most widely spoken Indo-Aryan language, with over 500 million speakers. It is the official language of India and is also spoken in Nepal, Pakistan, and Bangladesh. Sindhi is a language spoken by about 20 million people in Pakistan and India. Oriya is a language spoken by about 35 million people in India. Gujarati is a language spoken by about 60 million people in India and Pakistan.
Urdu is a language spoken by about 100 million people in Pakistan and India. It is the official language of Pakistan and is also spoken in India, Bangladesh, and Afghanistan. Urdu is a mix of Persian, Arabic, and Hindi. It is written in the Perso-Arabic script.
The word that is different from the rest is Urdu. The other four words are all Indo-Aryan languages, while Urdu is a member of the Indo-Iranian language family.