a shit

If you want to have an article try...
'That's such a load of bull-shit'
'He gave me a crock of shit'
I think the key reason for the absence of a article is the colloquial nature of these phrases.

Merge is correct. It's shortened to be coloquial. Just like when people say "Don't give me attitude" instead of "He has a bad attitude." But the reason why there is no article is because in the first two cases "shit" is used to sort of describe the situation or how bad something is. Whereas in the third example, "shit" is used as a noun, as in a physical thing, just like you could use "I don't give a rat's ass". In the first two, bull-shit and shit are used to illustrate the degree of negativity.

Could perhaps the "I don't give a shit" use the word "shit" in the verb form rather than the noun? As in "make a run for it". Just MHO.

I just tought of one more. What is the plural form of shit? Yes! A piece of shit. So, "that is bull shit" wouldn't need an "a" in it. Since it is shit in the plural form. Or am I completely wrong here? And of course it is shortened from "(a load) of bullshit" or any other modified to the uncountable noun.

Hmmm...I think Merge is the closest to how I feel about it. "a shit" imparts emphasis, and is less meaningful than the phrase "I don't give two shits!". This is very a colloquial expression, however, and the rules governing its final form are not likely to be well understood to anyone.

this is such bullshit
--means that this thing has the property of bullshit

this is such a bullshit
--means that this thing is the same as bullshit

for example
he is red = his color is red...perhaps he is very hot.

he is a red = he is a communist

the difference between all your examples is whether you are describing the object or acting on the object. a descriptive form could be i dont give shit = i give nothing. whereas an action would be i dont give a shit = i dont care. each has a different meaning.

if you think shit is a difficult word, i think you would love this article

http://www.letssingit.com/?http://www.letssingit.com/dennis-leary-usage-of-the-word-fuck-94xbg4j.html

I think stizzous is close but maybe this could be explained a little better.

The first comment is exactly right: "This is bullshit" is a metaphor implying that the thing in question is similar to bullshit. Since bullshit has little value, the implication is that the object of discussion similarly has little value.

In the second instance, I think there an implied word has been left out. "He gave me shit" is basically the same thing as "He gave me some shit". Shit, in this case, is a substance, not an object. It's an uncountable noun as you like to say here. An article wouldn't make sense.

In the last instance, we're talking about an object, not a substance. "I don't give a shit" is talking about a particular shit, that is to say, the results of a session of shitting; a turd. It's a particular thing and deserves an article for that reason.

Nouns can often be used in both count and noncount senses. It could be argued that "dog" is strictly a "count" noun, but (in the memorable words of my linguistics prof) how about in this case?
"Rounding the corner on my bicycle, I saw a Volvo encounter a poodle in the worst possible way. All it took was two seconds, and WHAM! -- dog all over the road."
Wouldn't the three instances of "shit" fall into these categories?
And sorry, Merge, but your comments are the worst kind of wrong.

It has to do with whether it's treated as a substance or as an object. Most nouns are either one or the other: 'chalk' and 'water' are substances (you can't say 'a chalk' or 'a water'); 'piece' and 'body' are objects (so you can say 'a piece of chalk' or 'a body of water', but not 'it was full of piece,' or 'I was covered in body').

'Shit' can be used either way. So we can talk about 'a shit' when we mean a particular turd, or just 'shit' when we're talking about the substance.

"That's bullshit" and "He gave me shit" = shit as a substance
"I don't give a shit" = shit as an object (still a weird way to phrase it)

There are still odd things about colloquial phrases like those, though. How about, "I took a shit." Shouldn't it be, "I left a shit"?

My two cents worth:

There are at least two forms of the word here. If you can substitute the word "nonsense" in the sentence, then don't use the article. If you can insert the words "piece of" before the word in question, then use the article "a". If neither word will quite do, it depends on context.

Compare:

"Don't tell me that, man, that is just shit/nonsense."

"Look, I really don't give a [piece of] shit, you [piece of] shit."

"I wanted to get high, so I got this guy to sell me some shit." (Drugs, American vernacular)

"That explanation is for shit." (Not sure where the "for" comes in, but you can use "nonsense" for the phrase.)

The word shit could be considered a slang term for feces could it not? If that is true then trying to figure out the correct plural of shit is impossible because it would not follow the same rules as the rest of the Engligh language. Therefore; I would think that anyway you wanted to use this word would infact be correct, somewhat similiar to the usage of the "F" word, often used as a noun, a verb, an adjective, etc.

"The word shit could be considered a slang term for feces could it not?"

(grin) Umm, yeah. Actually "shit" is English, while "feces" is a Latin borrowing. The words in English that derive from the Latin word are used almost exclusively in a formal, medical sense.

"If that is true then trying to figure out the correct plural of shit is impossible because it would not follow the same rules as the rest of the Engligh language. Therefore; I would think that anyway you wanted to use this word would infact be correct, somewhat similiar to the usage of the "F" word, often used as a noun, a verb, an adjective, etc."

No! As a matter of fact, "shit" is a perfectly good English word, grammatically speaking. As a verb it conjugates in a regular way, as a noun its declension is straightforward, everyone knows what the word means, and there is nothing complicated about it whatsoever as far as the "rules" are concerned.

un countable noun

when and how to use would and could?
with examples