horseshit

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Vulgar The excrement of a horse.
• noun Vulgar Slang Meaningless or insincere talk or action; nonsense.
• interjection Vulgar Slang Used to express disagreement or exasperation.

from the GNU version of the Collaborative International Dictionary of English.

• noun Vulgar slang A ludicrously false statement.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun vulgar, slang Serious harassment or abuse.
• noun vulgar, slang Blatant nonsense, more likely stemming from ignorance than any intent to deceive.
• noun vulgar, slang bullshit

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun obscene words for unacceptable behavior