literally

First recorded in 1525–35; literal + -ly

Since the early 19th century, literally has been widely used as an intensifier meaning “in effect, virtually,” a sense that contradicts the earlier meaning “actually, without exaggeration”: The senator was literally buried alive in the Iowa primaries. The parties were literally trading horses in an effort to reach a compromise. The use is often criticized; nevertheless, it appears in all but the most carefully edited writing. Although this use of literally irritates some, it probably neither distorts nor enhances the intended meaning of the sentences in which it occurs. The same might often be said of the use of literally in its earlier sense “actually”: The garrison was literally wiped out: no one survived.

The adverb literally was formed in English by adding the adverbial suffix -ly to literal, an adjective borrowed from Late Latin litterālis “of or relating to letters or literature.” (When we say “the letter of the law,” we are referring to its literal, or most obvious, meaning that follows the actual wording of the law.)
But it is of no use to complain that literally properly means “actually; without exaggeration,” the exact opposite of figuratively. That battle is almost lost; popular usage has nearly won, so that literally may also be used to mean “in effect; very nearly; virtually.” In fact, this meaning is now quite common, with literally being used to intensify a metaphorical expression, as in “He literally died when he found out the truth.”
Another usage battle was lost well over two thousand years ago, when Cicero, the Roman Republic’s greatest orator and man of letters, in his dialogue Brutus, yielded his own older “correct” pronunciation of certain words to the more recent popular “incorrect” usage, changing his own pulcer “beautiful” to pulcher, triumpus “triumph” to triumphus, and Cartāgo “Carthage” to Carthāgo. (Notice that it is the “vulgar” spellings that are current in English pulchritude, triumph, and Carthage ). In each of the spelling changes, “c” to “ch,” “p” to “ph,” and “t” to “th,” the “h” represents aspiration of the consonant (voiceless stops in these cases). Aspirated voiceless stops were a feature of the pronunciation of the uneducated populace who aspired to but overshot the pronunciation of educated speakers.

The use of literally as an intensifier is common, esp in informal contexts. In some cases, it provides emphasis without adding to the meaning: the house was literally only five minutes walk away. Often, however, its use results in absurdity: the news was literally an eye-opener to me. It is therefore best avoided in formal contexts