I know there are plenty of words that use the -st ending: wouldst, whilst, unbeknownst, etc. but I'm not really sure what it means to add an -st suffix to a word. What does it mean to add the suffix? How can I tell what words can take the -st suffix? Are there any modern words that can take the suffix and not have people look at me in a strange way?

  • For whilst, amongst, amidst, it's a remnant of archaic English grammar that I don't understand ... I hope somebody will give a good explanation in an answer. Aug 21, 2013 at 2:58

3 Answers 3


Your -st endings are two different grammatical animals. In wouldst it is the standard verb ending for the archaic second person singular familiar thou:

Cleopatra. O, I would thou didst,
So half my Egypt were submerged and made
A cistern for scaled snakes! Go, get thee hence:
Hadst thou Narcissus in thy face, to me
Thou wouldst appear most ugly. He is married? — Antony and Cleopatra 2.5.1174–8.

Unbeknownst, however, is another creature entirely, even among its peers.

Emerging in both British and North American print sources in the 1830’s, unbeknownst was originally a colloquialism coined on the pattern of much older words such as unawares (1530s) or always (early 13th c.), adding the etymologically intrusive final t of amongst, whilst, betwixt, etc. The s is a remnant of the genitive case, often used in Old and Middle English to form adverbs from nouns or adjectives.

I think that 'ere Ingian must have been the devil, or how could he come so sudden and unbeknownst upon me, … John Richardson, Wacousta, or, The Prophecy: A Tale of the Canadas, London, 1832.

“I remember my respectable first-floor, Monsieur Boncoeur, bringing home a piping bullfinch last year he’d bought on the Boulevards, whose red breast washed off the first showery day, all as one as Ma’mselle Isoline’s rouge after a flood of tears in a melodrame! The poor dear gentleman had half a mind to have up the seller of the impositious bird before the commissary of the district; only, as he’d paid for it with an old coat unbeknownst to his valet, and an old coat not being lawful coin of the realm, there was a doubt in his mind about his power of bringing the vagabond to justice.” — Toby Allspy (pseud.), “Adventures in Paris: The Five Floors,” Bentley’s Miscellany 2 (1837), 501.

“No matter,” added Lynx authoritatively ; “getting into another man’s barrel unbeknownst to him in the night-time, is burglary.” — Joseph C. Neal, Charcoal Sketches; or, Scenes in a Metropolis, Philadelphia, 1839.

The word also appears in an 1875 Sussex dialect dictionary, suggesting the usage is older than its first appearance in print:

Unbeknownst. Unknown.
“All I can say is, if he comes here, it's quite unbeknownst to me.” — William Douglas Parish, A Dictionary of the Sussex Dialect and Collection of Provincialisms, Lewes, 1875, 127

Even so, the word is a likely candidate for the last coinage in English using the adverbial genitive.

The adverbial genitive, though no longer productive, is a feature especially common to West Germanic languages. It’s hiding in plain sight in many common English words: once, twice, sideways, backwards, forwards and the alternatives amongst, whilst more common to British usage.

This means that you can no longer form words using the adverbial genitive -s, and unless you’re in a Shakespearean play, you won’t be using the thou form of English verbs anytime soon.

  • Wow, 5 years later this answer is absolutely is the best. Thank you for taking the time to answer and old question of mine.
    – Justin808
    May 10, 2019 at 23:11

Long long ago in a galaxy far far away...uh, well, not really.

English used to have a more complex grammar than it does presently. It is a Germanic tongue and so retains a touch of German in old, not so much used, forms.

The -st you refer to are from the old second person singular. Wouldst:

  • Wouldst = Wouldest thou - would you
  • Wouldest thou that I could = Wouldst that I could = would that I could

While "wouldst" is uncommmon, I have heard "unbeknownst" used much more commonly: "Unbeknownst to me, she was married." This would likely not sound odd at all to me, just perhaps a touch formal.

Another one that is completely disused is "durst", which is the second person singular of "to dare".

ETA: Originally, I had included a couple of paragraphs about "whilst" as a verb, but a comment by @siride (that I didn't examine closely until a year after posting this answer) clued me into the fact that I was wrong about "whilst". I refer you to the comments below for more data on that.

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    The odd thing about this one is that Americans have enthusiastically taken up the archaic form unbeknownst in recent decades, despite the fact that they clearly have no time for whilst. Thou wouldst hardly have expected Americans to be leading the field in terms of reviving archaic forms! :) Aug 21, 2013 at 3:39
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    "While we watch Rugby, the Americans watch Football.": A Brit would say "Americans watch American football", as "football" in BrE = "soccer" in AmE. :-) Aug 21, 2013 at 11:20
  • Yes, you're more correct than I was. Aug 22, 2013 at 0:24
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    "whilst" has nothing to do with the 2nd person singular as it clearly isn't a verb. It's in the same group as "amongst" and "amidst", where the "t" was added to a form already ending in "s" to achieve some sort of euphony (German has done similar things: "niemand", "jetzt", etc.)
    – siride
    Aug 25, 2013 at 16:47
  • @siride, that's a good point, however there actually IS a verb "to while", and that's what I was thinking of. Perhaps I was incorrect in associating it with this question. "To while away" = to pass time idly. Hmmm. Aug 25, 2014 at 18:05

For unbeknown vs. unbeknownst: http://fandom-grammar.livejournal.com/39346.html which would probably explain the others also. "Whilst" I've heard British people use working with them, but everything they say sounds funny and lovely!

  • I lived there for a few years, once upon a time, and I agree that "everything they say sounds funny and lovely!" Although it is not so much what they say, but how they say it! Aug 21, 2013 at 16:43

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