Yes you can.
For example: My hair is finer than yours.
Another example: Nothing could be finer than to be in Carolina in the winter.
It is comparatively easy to use "comparatively" in a sentence.
No.
I wouldn't use a semicolon in a conditional (if) sentence. Semicolons can join two independent clauses without a conjunction. The "if" clause in a conditional sentence is dependent, not independent.
I mightn't use that word.
full stop
He put medicine on his swelling thumb. She had a ring on her ring finger, her index finer, and her thumb. At night the baby sucks his thumb.
Use finer grade sand paper
Jem Finer's birth name is Jeremy Max Finer.
Finer energy, such as nuclear energy, has its own set of pros and cons, including safety concerns, waste disposal issues, and potential environmental impacts. Additionally, the technology and infrastructure required for harnessing and utilizing finer energy sources may not be as widespread or developed as traditional energy sources like fossil fuels and renewable energy.
Sarah Dawn Finer's birth name is Sara Dawn Finer.
Unless this is the title of a book, movie, or song, the word finer would not be capitalized. The word Nothing is capitalized as the first word in the sentence, and South Carolina is a proper noun (a state). Of course, the song lyric is actually "Nothing could be finer than to be in Carolina" from the song "Carolina in the Morning" (1922).
Hagar Finer was born in 1984.
Herman Finer was born in 1898.
Herman Finer died in 1969.
Samuel Finer was born in 1915.
Samuel Finer died in 1993.
The Finer Things was created in 1964.