Crypto-Hinduism is the secret adherence to Hinduism while publicly professing to be of another faith; practitioners are referred to as "crypto-Hindus" (from Greek kryptos - κρυπτός, 'hidden').
Crypto-Hinduism was observed during a period of forced religious conversions in South Asia, as well as suspected against Hindus who were forcibly converted to the religion of the invaders or colonizers.
For example, states Bardwell Smith, Khusru Khan, a convert from Hinduism to Islam and an army commander who led plunder raids against Deccan kingdoms, was towards the end of his life "accused by Turkish nobles of harboring crypto-Hindu tendencies, a false charge but one which reflected genuine factional divisions and prejudices within the Muslim ruling class".
These two communities were perceived as a security threat due to their established reputation for joining forces to overthrow Christian rulers in the Iberian peninsula.
[11] Despite partition, religious syncretism remains present in the country, with some Muslim devotees continuing to visit shrines dedicated to Hindu and Sikh saints.