Manx
Concise Oxford English Dictionary © 2008 Oxford University Press:
Manx/maŋks/
▶noun the Celtic language formerly spoken in the Isle of Man, still used for some ceremonial purposes. ▶adjective relating to the Isle of Man or its people or language.
– derivatives
Manxman noun (pl. Manxmen),
Manxwoman noun (pl. Manxwomen).
Manxman noun (pl. Manxmen),
Manxwoman noun (pl. Manxwomen).
'Manx' also found in these Oxford entries:

