I suspect `nigh` (as in nearly or almost). https://www.dictionary.com/browse/nigh https://www.dictionary.com/browse/nigh Nigh on impossible is a stock phrase m

I suspect `nigh` (as in nearly or almost). https://www.dictionary.com/browse/nigh https://www.dictionary.com/browse/nigh Nigh on impossible is a stock phrase meaning "virtually impossible".