The Laodicean Church was a Christian community established in the ancient city of Laodiceia (on the river Lycus, in the Roman province of Asia Minor). The church was established in the earliest period of Christianity, and is probably best known for being one the seven churches addressed by name in the Book of Revelation.
From Revelation (3:15-16)
I know your works; you are neither cold nor hot. I wish that you were either cold or hot. So, because you are lukewarm, and neither cold nor hot, I am about to spit you out of my mouth
It has been suggested that the metaphors have been drawn from the water supply of the city, which was lukewarm; hence the use of Laodicean in English for the neutral, lukewarm, or indifferent; especially in religious controversies.