The phrase "a peculiar reason" is correct and usable in written English.
It can be used when referring to a reason that is unusual or strange in some way.
Example: "She had a peculiar reason for arriving late to the meeting, which left everyone curious."
Alternatives: "an unusual reason" or "a strange reason".
Senator Lindsey Graham of South Carolina, for example, said the fight over the debt ceiling was good for Democrats, but for a peculiar reason.
"One objection against electors was the danger of their being corrupted by the candidates, and this furnished a peculiar reason in favor of impeachments whilst in office," Mason pointed out.
A Pennsylvania chaplain noted a peculiar reason that two men in the regiment claimed for a discharge: "Both of them have been married for some years; and yet such are the pernicious effects of the early indulgences, that now they frequently have nocturnal emissions, foul dreams, etc. — besides rheumatism and general debility — such as renders them unfit for service".
There's an O. Henry coda: the strange, small revelation that he'd become a dentist for the most peculiar reason, inspired by a TV Christmas special.
The equivalent shift in Hollywood movies didn't happen until the nineteen-eighties, for a few peculiar reasons.
And a lack of time always leads to an opening of the heart, for some peculiar reason.
It was supposed to read "What doesn't kill you, only makes you stronger" – a popular paraphrase of the Friedrich Nietzsche quote – written, for some peculiar reason, in Hebrew.
:P (I just googled newsweek satoshi and see they've got an article about "the real face behind bitcoin" but for some peculiar reason it claims I've reached my 5 free articles per week, which can't be true because I've not been there in the last week at all).
First, for some peculiar reason, the live image in the viewfinder freezes for half a second as your finger pushes down the shutter.
Peter must have seen him do this, but for some peculiar reason he does not tell on him.
This sentence, incidentally, puts the quietus on the ridiculous word "platonic" that for some peculiar reason still crops up in discussion of the story.
