Aphabetic letter pairs in words

NW - now

NX - narthex

NY - navy

NZ = nertz

OA = ocarina

OB = outclimb

OC - A very bad TV show.

Oh, all right: obec (the Czech and Slovak word for a municipality)

OD - overdosed

OE = office

OF - off

OG- oolong

OH - ostrich (or Oshkosh)

OI - octopi

OJ - OJ (as in orange juice)

OK: oink

OL = optical

OM = optimism

ON - Omicron

OO- oregano

OP = outcrop