Lie, falsehood, untruth, fib, misrepresentation, story are comparable when they mean a statement or declaration that does not conform to the truth.
Lie is usually felt to be a term of extreme opprobrium because it implies a flat and unquestioned contradiction of the truth and deliberate intent to deceive or mislead.
Falsehood may be both less censorious than lie and wider in its range of application. The term need not imply sinfulness or criminality, for it applies not only to lies, but to such fictions as literary fictions, polite fictions, and legal fictions and then contrasts most directly with fact. Like lie, the term implies known nonconformity to the truth, but unlike lie, it does not invariably suggest a desire to pass off as true something known to be untrue.
Untruth is often euphemistic for lie or falsehood and may carry similar derogatory implications or it may be selected because of mitigating circumstances. Sometimes, however, untruth may apply to an untrue statement made as a result of ignorance or a misconception of the truth.
Fib is an informal or childish term for a trivial falsehood; it is often applied to one told to save one's own or another's face.
Misrepresentation applies to a misleading and usually an intentionally or deliberately misleading statement which gives an impression that is contrary to the truth; the term implies glossing over defects or weaknesses (as in something offered for sale) or placing the emphasis upon details that highlight a character, an occurrence, or a train of events rather than on those that in reality marked it.
Story (see also ACCOUNT 2 ) in the sense relevant to this discussion is an informal term used chiefly by or with reference to children in place of any of the preceding terms, especially falsehood, untruth, and fib.