Jtdylktuy

The word "snipped" can seemingly be used to mean "said in a snippy manner":

"No," she snipped, obviously annoyed

—http://rosemarinetheater.blogspot.com/2013/05/white-boy-can-rap-looking-at-benny-in.html

...the former president was emphatic. "No," he snipped.

—http://www.washingtonpost.com/blogs/post-partisan/wp/2016/02/03/no-bernie-sanders-is-not-barack-obama

"No," she snipped. "You're American, aren't you? You're not very popular here today."
—http://www.city-journal.org/html/london-peace-marchers-say-long-live-intifada-9989.html

Yet no dictionary (of the dozen or so I consulted) documents this usage. Not even the OED [paywall], which documents every obscure meaning every word has had over the past 500 years. Not even urbandictionary, in which anyone can add words and definitions with no editorial oversight.

Is this meaning too rare for dictionaries to document? It strikes me as a somewhat unusual but not obscure construction when I run across it. But of course it's difficult to google for a word used with a specific meaning when that word also has a vastly more widely used meaning. (You'll find a mix of hits and false positives searching for exact phrases such as "no she snipped," which is how I discovered the above citations.)

Is this meaning too new to have made it into any dictionaries? The oldest of the above citations is from 2003, and again, my sense is that it's been around longer than that (though again, without a way to effectively search, it's hard to say).

Is this usage actually an erroneous substitution for another word? "Sniped," for instance, can also be the verb in a dialogue tag, but it has a different meaning (one which could conceivably apply in the third citation above, but not the first two). I can't think what other word might be intended.

Has this meaning been collectively overlooked by all the major dictionary compilers? This seems extremely improbable, yet Sherlockianly correct.

Am I overlooking another possible explanation?

As chasly from UK suggested in a now-deleted answer to this question, snip as a verb meaning "speak curtly or snappishly" probably originated as a back-formation from the adverb snippily or the adjective snippy, which Merriam-Webster's Eleventh Collegiate Dictionary (2003) defines as follows:

snippy adj snippier. -est (ca. 1848) 1 : SHORT-TEMPERED, SNAPPISH 2 : unduly brief or curt 3 : putting on airs : SNIFFY — snippily adv

The phrase "said snippily" goes back to at least 1914 in Google Books and Hathi Trust search results. From Rose Macaulay, The Making of a Bigot (1914):

Mrs. Denison said, snippily, "Dorothy ought to know better," at the same moment that Eddy said, "It's a jolly little League, apparently. Quite full of truth."

From Shirley Seifert, "The Nicest Boy and What the Smartest Girl in the Office Did to Him," in The Delineator (July-August 1920):

"Isn't it a cold night?" she said snippily to the gloomy, immaculate young man who called for her at eight the night of the party.

Also, from a 1921 translation by Philip Allen of Johanna Spyri, Heidi:

But it was hardly any time at all before Tinette thrust the tip of her nose in at the door and said snippily, just as always—"Off with you to the library!"

...

Bring me this box full of nice fresh cakes like those we have with cofee, Tinette," said Clara, pointing to a little chest which had been standing there for just this purpose for a long time. The maid seized the object by one corner and let it dangle carelessly from her hand. After she had shut the door behind her, she said snippily—"Little things like that are no trouble at all."

Evidently, "snipped" has had more that a century to emerge as a short form of the phrase "said snippily."

Something similar seems to have happened with such verbs as crabbed, grumped, and huffed, which are likewise sometimes used as short-form alternatives to "said crabbily," "said grumpily," and "said huffily," respectively. But the Eleventh Collegiate accords each of these meanings a place in its dictionary:

crab vt ... 2 : to complain about peevishly ... vi : CARP, GROUSE {always crabs about the weather}

...

grump vi ... 2 : GRUMBLE, COMPLAIN ~ vt : to utter in a grumpy manner

...

huff vi ... 2 a : to make empty threats : BLUSTER ... vt ... 3 : to utter with indignation or scorn

If snip in the sense of "say snippily" continues to appear in published works, it is only a matter of time before an additional entry for snip as a transitive verb, along the lines of "to utter curtly or snappishly," appears in some future Merriam-Webster's dictionary. In the long term, it's hard to say whether the word's prospects will be helped or hindered by its visual and aural similarity to snap, sniff, and snipe—all of which can be used as verbs in kindred senses.

This is an interesting question, in the sense that it touches upon the matter of this site: what precisely allows some feature of language to count as ‘usage’.

You might start by asking a different question: ‘criteria for adding a word to a dictionary’. It’s not exactly your question, which is about new uses of old words, but it is a start.

Here is what Merriam Webster says:

Criteria for adding a word to the dictionary
To be included in a Merriam-Webster dictionary, a word must be used in a substantial number of citations that come from a wide range of publications over a considerable period of time. ... The number and range of citations needed to add a word to the dictionary varies.

That used by Oxford Dictionaries is broadly consistent with that. Of course, terms like ‘a substantial number’ and ‘wide range’ of publications and ‘considerable’ period of time. Infuriating as the vagueness may seem, it is inevitable: any boundary would be arbitrary and so possibly restrictive.

You should look carefully the idea of range of publications and period of time. The issue is more than the number of uses.

Nevertheless, OED, Merriam Webster and most major dictionaries are keen not to fall behind the natural development of the English language. So OED has a public site:

public.oed.com

It gives you detailed guidance how to engage and propose words/uses not currently cited.

It appears sniped and snipped are in many cases used interchangeably. Your reference American Dictionary:

snipe (snīp)

intr.v. sniped, snip·ing, snipes
1. To shoot at individuals from a concealed place.
2. To shoot snipe.
3. To make malicious, underhand remarks or attacks.

and the OED cites sniped

fig. To assault with harsh sly criticism; to rebuke or censure
sharply; to make a carping attack at (someone).

As in:

1979 A. Hailey Overload i. xiv. 79 The press representatives had
eaten and imbibed with gusto, then in published reports, some had
sniped at GSP & L for extravagant entertaining at a time of rising
utility bills.