Incredibly is the word you reach for when very is not strong enough. Incredibly hot, incredibly kind, incredibly boring — it turns the dial up on whatever adjective comes next.
Taken apart, it means 'in a way you could not believe', and that older sense is still alive at the front of a sentence: 'Incredibly, nobody was hurt.' There the speaker is telling you the fact is hard to swallow, not that it was extreme. Position in the sentence is what separates the two. In speech the word has been worn smooth — someone who says the film was incredibly good means very good, with no disbelief in it at all. Its family is credible, incredible and credit, all built on believing; incredulous belongs to the person doing the disbelieving, not to the thing.
1adverbextremelyTo a very great degree; extremely.
“The flat was incredibly cheap for that part of town.”
synonyms: extremely, remarkably
2adverbincrediblyIn a way that is hard to believe.
“Incredibly, the parcel arrived the next morning.”
synonyms: unbelievably, astonishingly
Too few real examples of this word to estimate which sense is commonest.
Proto-Indo-European
*ḱerd-
Latin
incrēdibilis — that cannot be believed
Middle English
incredible
English
incredible
English, today
incredibly
Built from
From incredible + -ly. incredible comes from Middle English incredible, from Latin incrēdibilis (“that cannot be believed”), from in- (“not”) + crēdibilis (“worthy of belief”), from crēdō (“believe”), equivalent to in- + credible.
Etymology from Wiktionary, CC BY-SA