a not-entirely-true or documentable "fact" that can be used alone or used to embellish a story;

see Anneism

1)A fact that may or may not be true, but is trivial in nature. The source of the factoid has questionable authenticity.

2) A verified fact in a compact sentance.

a presumed fact(based on other words with the suffix -oid)

A fact so awesome that it have to be true and used to embellish a story.
Checking for authenticity is not required.

an alternative way of expressing the somewhat offensive term fucktard in polite company

A very small fact. Usually used when one wishes to express what a small fact his fellow peer has just spoken upon.

The word can also be used as an insult, in the simple context of expressing that the speaker of the fact is actually saying such a small fact that it is a factoid, therefore being painfully obvious. Sort of another way of saying no shit sherlock.

Fac-toi-ded: Factoided is the verb used to announce someones previous statement or sentence was factually incorrect.
The word derives from Maeve Murphy's Gibberish.