Impeccable describes that which is free from fault, error, or blame. It is a synonym of flawless.

// Although the restaurant was a bit expensive, we found its memorable cuisine, luxurious decor, and impeccable service to be well worth the price.

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"Meghan Markle turned 42 years old on August 4th, and her style is as impeccable as ever." — Emily Tannenbaum, Glamour, 5 Aug. 2023

The word impeccable has been used in English since the 16th century. It comes from the Latin word impeccabilis, a combination of the Latin prefix in-, meaning "not," and the verb peccare, meaning "to sin." Its original meaning hewed close to its root: impeccable meant "not capable of sinning or liable to sin." (It has a rare but pleasingly logical antonym in peccable, meaning "liable or prone to sin.") Peccare has other descendants in English: there is the noun peccadillo, ("a slight offense"), adjective peccant ("guilty of a moral offense" or simply "faulty"), and the noun peccavi, which in Latin literally means "I have sinned" but in English refers to an acknowledgment of sin. Nowadays, impeccable is more commonly used in the secular sense to mean "flawless," as in "impeccable taste in music" or "their craftsmanship is impeccable."