A person who has had a lot of experience of a particular activity:

• Veteran: 
English meaning: A person who has had a lot of experience of a particular activity.
Bangla Meaning: অভিজ্ঞতাসম্পন্ন ব্যক্তি। 
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অন্যদিকে, 
• Amateur: 
One who plays a game for pleasure and not professionally -Amateur.
Bangla Meaning: শৌখিন চিত্র বা সংগীত বা নাট্যশিল্পী; অপেশাদার ক্রীড়াবিদ।

• Genius: 
English meaning: very great and rare natural ability or skill, especially in a particular area such as science or art, or a person who has this
Bangla meaning: প্রতিভা; সৃজনী ক্ষমতা
Plural form: Genii/ Geniuses.

• Fastidious (Adjective):
English meaning: Showing or demanding excessive delicacy or care,
Bangla meaning: খুঁতখুঁতে; দোষ ধরতে তৎপর

Source: Accessible Dictionary by Bangla Academy and Oxford Learner's Dictionary