Spanish term (edited): Soltó un taco.

Or: "spewed" instead of "blurted."

Here "taco" means "swear word" or "expletive."

See: www.spanishdict.com/translate/taco

In Spain, "Soltar tacos" means to cuss / swear.

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Note added at 13 mins (2013-11-20 16:27:41 GMT)
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See think link:
http://www.wordmagicsoft.com/dictionary/es-en/soltar tacos.p...

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Note added at 13 mins (2013-11-20 16:28:03 GMT)
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this***

Taco = rude word / swearword.

"He/she made a rude comment. It was barbaric, verging on blasphemous. "

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Note added at 14 minutos (2013-11-20 16:28:27 GMT)
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Another idea:

"HE/SHE MADE AN OBSCENE REMARK / COMMENT"

Rupert Everett's obscene gaffe on live TV | Showbiz | News | Daily ...
www.express.co.uk › News › Showbiz‎
Sep 19, 2012 - ... and HOLLY WILLOUGHBY squirming with embarrassment on Wednesday (19Sep12) when he made an obscene comment live on air.

I recommend just using the verb. I would do it like this:

She swore. The expression she used was outrageous, almost blasphemous. But it was also ingenious, which made it less shocking.

Obviously it could be "he" instead of "she"; you will know from the context which it is.

This "taco" must have been a phrase. A single word can hardly have been "ingenioso", but a combination of two or more words could be. "Taco" or "palabrota" can be phrases, but the most common English equivalents are "swear word" (British) or "curse word" (American), which refer to single words and are therefore unsuitable here.

An expletive can be a phrase, but to me it's a pretty formal word, almost legalistic, and stylistically unsuitable. (It always makes me think of "expletive deleted" in the transcript of the famous Nixon White House tapes.).

"An obscenity" could be used, and in fact if you want to do this with a noun that would be my recommendation. You could say "She let out an obscenity". But in fact I don't think that it's a good idea to emulate the repetition of "taco" in English at all. It works in the Spanish original but in English it would be clumsy.

The normal way of saying "soltar un taco", in isolation, is simply "to swear". This is the standard verb in British English, and it's in Merriam-Webster with this meaning, so I presume it's understood in America. But I think "to curse" is more usual in American English. "Curse word" is used in American English, but not in British English, where the equivalent is "swear word".

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Note added at 2 hrs (2013-11-20 18:47:22 GMT)
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It's a matter of style. "Soltó un taco" is brief, abrupt. Anything along the lines of "he let out an expletive" loses that punchy rhythm, and with it the force of the original. And honestly, who uses "expletive" in everyday speech? I don't know if people do in the US, but it really seems formal to my British ear.