adherent of	a person who supports a particular idea or party
convert to	someone who has taken on a new set of beliefs
fanatic	someone with a very strong belief (negative)
radical	someone who believes there should be extreme political change, either a left- or right-wing
reactionary	someone opposed to change or new ideas (negative)
bigot	someone with strong unreasonable beliefs who thinks that anyone with other beliefs is wrong
assumption	unquestioning acceptance that something is true
to derive from	to have one's origins in
to eradicate	to abolish, to get rid of
postulate	basic principle
consciousness	awareness
to usher in	to introduce
credible	believable
credulous	too willing to believe what you're told
incredulous	not wanting or able to believe something
credence	acceptance that something is true
to give/lend/add credence to sth	to accept sth as true
gullible	easily tricked into believing things that may not be true
ingenuous	trusting, sincere, often in a way that seems foolish
plausible	convincing
implausible	unconvincing
to ascribe/attribute sth to sb	to consider sth to be caused, created or possessed by a person or a thing
tenet	one of the principles on which a belief is based
to give someone the benefit of the doubt	to accept that someone is telling the truth even though it is not certain
to take sth with a pinch of salt	to not totally believe what you're told