'Old Peculier' was one of my favourite beers when I lived in UK.
It is not, unfortunately, available in Thailand.
You do need to get the spelling right however - Peculier not Peculiar , although I think that spelling is now obsolete except on beer bottles.
Peculier is a noun, not an adjective, an old religious term for a parish which was not part of a regular diocese.
I think it was also used of a monk who wasn't attached to any particular monastery. The labels on the bottle have a picture of a monk.
The Chapel of St Mary Undercroft in the basement of the Houses of Parliament - it was the setting for a key scene in the BBC thriller serial Apple Tree Yard - is a Royal Peculiar. It is not part of a regular diocese.