Incredible means so amazing that it is hard to believe. An incredible view, an incredible result, that is incredible.
The literal meaning — not credible, not believable — survives in careful writing: an incredible claim is one you should doubt. In speech the word has inflated into a general intensifier meaning excellent, and both uses are current, which occasionally produces genuine ambiguity. Note incredibly, which is almost always just very: incredibly useful, incredibly tired. And keep incredible apart from incredulous, which describes the person who cannot believe it rather than the thing they cannot believe.
1adjectiveincredibleSo amazing that it is hard to believe.
“The view from the top is incredible.”
synonyms: amazing, extraordinary, unbelievable
2adjectiveimpossibleImpossible to believe.
“His account of the evening was frankly incredible.”
Too few real examples of this word to estimate which sense is commonest.
incredible is a degree of amazement.
Also accepted in games: unbelievable
Latin incredibilis is in-, not, plus credibilis, believable, from credere, to believe — the same verb behind credit, creed and credentials. The word means exactly what its parts say, and the modern sense of wonderful is what happens when a word is used for emphasis for four hundred years.
Proto-Indo-European
*ḱerd-
Latin
incrēdibilis — that cannot be believed
Middle English
incredible
English, today
incredible
Built from
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