'A person who believes that life is meaningless and rejects all religious and moral principles' -

• Nihilist (noun)
English Meaning: A person who believes that life is meaningless and rejects all religious and moral principles
Bangla Meaning: নাস্তিবাদী।

• অন্য অপশনগুলোর মধ্যে -

ক) Pacifist (noun)
English Meaning: A person who believes that war and violence are unjustifiable.
Bangla Meaning: শান্তিবাদী।

খ) Anarchist (noun)
English Meaning: Someone who wishes to destroy the existing government and laws
Bangla Meaning: নৈরাজ্যবাদী।

গ) Agitator (noun)
English Meaning: To make someone feel worried or angry.
Bangla Meaning: (বিশেষত রাজনৈতিক) আন্দোলনকারী।

Source:
1. Cambridge Dictionary.
2. Accessible Dictionary by Bangla Academy.
3. Oxford Learner's Dictionary.