[set fair (OP)]

I use new air.

[chris]

Hmm - can we have a clue?

[Bored chemist]

Is a rue wine
I USA Wiener
I rain US wee

[set fair (OP)]

Hmm - can we have a clue?

It isn't an anagram nor a crossword question. A word puzzle comes close. A correct answer would use the word only or unique,

[set fair (OP)]

OK the four words have something in common that no other words have.

[Bored chemist]

OK the four words have something in common that no other words have.

One thing they certainly have in common which no other words share is that they form the opening post of this thread.

[Petrochemicals]

You leave old gas ?

[set fair (OP)]

Last hint, if anyone is still bothered. Try writing down your thinking, Maybe looking at it will turn the light bulb on.

Answer tomorrow.

[jimbobghost]

you are the only extra terrestrial carbon based life form on earth.

[Petrochemicals]

A breath of fresh air ?

[set fair (OP)]

I eye aye
use ewes yews
new Knew gnu
air ere heir
Three words pronounced the same but with a different initial letter, the only ones.