What is the word for a person who thinks/afraid others can change them? [duplicate]

Question

To give some context,

A person believes somethings (for example religious practices) but if someone tries to prove that those beliefs are wrong, the person gets into defensive mode - and can even burst with anger or get ready to fight.

So, this is a person who wants to protect his/her beliefs and if someone shares their beliefs he/she thinks that they are attacking their personal beliefs. This person doesn't want to change their beliefs. They protect them with their life if needed.

FYI, in this context, belief is different than knowing things. We know we have two hands but don't believe it. a youtube link

What is the word for such a person? (I don't think it is believer)

Answer 1

Three words come to mind. Two nouns and one adjective that might conceivably be used as a noun.

Fanatic = person who has very extreme beliefs that may lead them to behave in unreasonable or violent ways

Cambridge dictionary

Diehard = someone who is unwilling to change or give up their ideas or ways of behaving, even when there are good reasons to do so

Cambridge dictionary

Obdurate (adjective) = 1a : stubbornly persistent in wrongdoing. “an unrepentant, obdurate sinner”

1b : hardened in feelings “The obdurate enemy was merciless.”

2 : resistant to persuasion or softening influences

Merriam Webster

Of the three I feel that fanatic may suit best where religion is relevant, diehard in more general or secular cases. It may sometimes be possible to use obdurate as a noun but only as shorthand as in “An obdurate man” = “An obdurate”

Answer 2

I suggest zealot, which Merriam-Webster defines as—

a zealous person

especially : a fanatical partisan

There's also this word (adjective) for such people—

dyed-in-the-wool

Thoroughgoing; out-and-out: a dyed-in-the-wool populist.