Nonpareil

Technically, this is a phrase, which has been misspelled as a single word for the benefit of English, and a foreign word (phrase), and therefore, excluded from discussion, but I'll make a a brief exception because it is French.

Nonpareil comes from the Latin "non" (not) and "par" (equal). Literally, not equal, but figuratively, for unequaled or without equal. Old French kept the "non" and used a diminutive "pareil" for equal, so the etymology to usage is still direct, as is the current spelling.

Which leaves us with usage, and here I will digress, since I think the appropriate usage would be to keep it as two French words "non pareil" and write it in italics to indicate the deliberate usage of a foreign language. This phrase is French, and should stay that way. She hopes that her theory will be non pareil when presented to the Court. Equally, she strives that her musicianship and preparation for rehearsals will be non pareil, and set the standard for other chorus members. Of course, if you insist, just take out the space and lose the italics and see if it doesn't look like a typo...