One who is filled with excessive enthusiasm in religious matters is called -

• "One who is filled with excessive enthusiasm in religious matters" is called - Fanatic.

• Fanatic (Noun)
- English meaning: Someone who has extreme political or religious ideas and is often dangerous.
- Bangla meaning: (সাধারণত ধর্ম) অতিশয় গোঁড়া ব্যক্তি।

• Other options:
- Egotist: A person who thinks that they are better than other people and who thinks and talks too much about themselves.
- Bangla meaning: আত্মপ্রচারক; স্বার্থপর ব্যক্তি।

- Agnostic: A person who believes that it is not possible to know whether God exists or not.
- Bangla meaning: জড়বস্তু ছাড়া অন্য কিছু বা ঈশ্বর সম্বন্ধে কিছুই জানা সম্ভব নয় বলে যে ব্যক্তি বিশ্বাস করে; অজ্ঞেয়বাদী।

- Rationalist: Believing in or connected with rationalism.
- Bangla meaning: যুক্তিবাদী ।

Source: Merriam & Webster Dictionary, Oxford Dictionary, Accessible Dictionary.