Commonwealther

[Luis Fok]

A person from, or resident of the Commonwealth of Massachusetts.
Origins:
Massachusetts does not lend itself well to the typical suffixes (-ian, -er, etc.) attached to the name of a place to refer to someone who is from that place (perhaps because the name is not of English origin.) Thus, commonwealther is used as a reference to the fact that Massachusetts is officially designated as a Commonwealth instead of a State (although there is no legal distinction between a “state” and a “commonwealth” in the United States.).
There are three other states in the US that designate themselves as Commonwealths (Kentucky, Pennsylvania and Virginia.) However, the usual suffixes are applied to them ([Kentuckian], [Pennsylvanian] and [Virginian]) without issue, and so a new word is not needed to describe a resident of one of those states.