Syncretism

Syncretism
This is the merging of differing systems of belief, and usually results in a new teaching or belief system. Obviously, this compromising, modifying and adding to the Bible is not compatible to biblical Christianity (Rev 22:18,19). We are not free to add to or take away from His revealed directions, regardless of human sincerity, the attractiveness of new ideas or the whims and opinions of secular society. The Bible is to remain the standard for belief and practice.

Hinduism and the New Age Movement (NAM) are examples of religious syncretism where there has been this blending of various religious systems. 

See also: belief/believe, compromise, doctrine, heresy, New Age movement.