He limited it to words that weren't "Scrabble words", that is, ones he recognized. Another rot13 pair of length 7 are purpura⇔Chechen, in my /usr/shared/dict/words. Pairs of length 6 are, cheery⇔purrel (what is 'purrel'?), greeny⇔terral (what is 'terral'?), orphan⇔becuna ('becuna' is a type of fish?).