(n., adj.) a word that becomes plural and then singular when successive Ss are added to it
Pluralize the word care, and you get cares. Add another S onto the end of that, however, and something a little bizarre happens: the plural noun cares turns into the singular noun caress. Duplicating the standard English pluralizing process essentially has the effect of cancelling itself out—and that makes care an example of what’s popularly known as a dual-identity word.
That, at least, is according to various wordplay aficionados, whose tireless work unearthing curiosities like these led to this term becoming somewhat established enough to be included in a 2001 Dictionary of Wordplay. But now we know what a dual-identity word is, one question remains: how many of them are there?
As always with things like this, that’s a question it’s almost impossible to answer exhaustively, thanks to the sheer breadth of some of the dictionaries available to wordplayers these days, and to the drifting nature of the parameters at work. Just how obscure are we allowed to go here? Do proper nouns count? Are spelling variations permissible? What about scientific terms, 1- and 2-letter words, borrowed words not fully naturalized in English, and everything else that might not pass muster?
Presuming that all the potential variables here legitimate, there’s a near endless list of examples. Granted, permitting single- and double-letter words here doesn’t produce anything too enthralling alongside the likes of a > as > ass, and mo > mos > moss. But following the timeline > timelines > timeliness example we posted on Twitter, there are quite a few more ‘–nesses’ that work here:
tartine > tartines > tartiness
deadline > deadlines > deadliness
saltine > saltines > saltiness
glassine > glassines > glassiness
...glassine being the name of an especially glossy paper, FYI. Like the prince > princes > princess example from our original tweet, feminine nouns prove useful here too:
millionaire > millionaires > millionairess
ogre > ogres > ogress
adventure > adventures > adventuress
esquire > esquires > esquiress
...though esquiress is a term not much used since the 1600s. The mora > moras > morass example we mentioned on Twitter is questionable too, because morae is the more typical plural of the word mora (a phonological unit of syllabic weight). Bend the rules to include variations and archaisms like this, however, and there are a few more duals to be had here:
large > larges > largess
abbé > abbés > abbess
bulgine > bulgines > bulginess
dure > dures > duress
...largess being a variation of largesse, bulgine being a variant of bullgine, a nineteenth-century word for a team locomotive, and dure being an old word meaning to outlast or endure. Dodge the rule that the final word needs to be a singular noun—and need instead only be an entirely new word—we can add even more:
kindle > kindles > kindless
hurtle > hurtles > hurtless
handle > handles > handless
needle > needles > needless
And finally, following the zebra > zebras > zebrass example, here are a final few dual-identities that are just too good not to mention.
bra > bras > brass
inkle* > inkles > inkless
nervine** > nervines > nerviness
...an inkle being a type of loom, and a nervine being a natural or homeopathic agent that affects the nerves.