Sem igual/sem paralelo/ fora de / sem comparação (Without equal, beyond compare); unique.
As a noun: "The nonpareil of beauty!"
Aan an adjective, before or after the substantive: "Portia Radcliff is an intellect nonpareil." It is, however, used more often before the modified noun, "Mark is a nonpareil salesman," unless it has a subordinate phrase, "Mark is a salesman nonpareil among those in sales here." But then adjectives with subordinate phrases are regularly placed after the noun they modify in English (e.g. "a yellow book" but "a book yellow with age")."