Yes, the word hoax is an abstract noun; a word for a deception. A hoax is an abstract concept.
No, hoax can be a verb or a noun. When used before other nouns (hoax letter, hoax caller) it is acting as a noun adjunct.
hoaxes The plural of hoax is hoaxes.
No. Both words are synonyms. True Hoax would be an oxymoron.
A Fraud
A hoax is a deliberate attempt to dupe, deceive or trick an audience into believing, or accepting, that something is real, when the hoaxster knows it is not; or that something is true, when it is false.
You can use it as a noun: The climate in this nation is nice. My geography always talks about the climate of the country that we are studying. You can use it as an adjective: Some think that climate change is a hoax. Others think that the threat of climate change is dangerous.
There was no hoax, the landings were real.
The duration of The Hoax is 1.93 hours.
It was not a hoax, it was real.
Bigfoot is hoax.
The ISBN of Beyond the Hoax is 0199239207.
Beyond the Hoax was created in 2008.
The Hoax was released on 04/06/2007.
The Production Budget for The Hoax was $25,000,000.
There was no moon hoax. The moon landings were real.
It was somewhat, unfortuantley, a hoax.
Bathtub hoax was created in 1917.
The Hoax was created on 2007-04-06.