Definition of "impeccably"

The great pianist was a prolific composer, who wrote impeccably for the piano.

1995, David Dubal, Art of the Piano: Its performers, literature, and recordings, page 433

It is difficult to distinguish one bourgeois from another: the grande bourgeoisie are impeccably dressed at all times and don't speak to anyone outside their own class; the bonne bourgeoisie are impeccably dressed and speak to everyone; the petite bourgeoisie are impeccably dressed and speak only to complain […]

1999, The Xenophobe's Guide to the French, page 17

In fact, even when I did make some small mistakes with grammar, people still said I spoke impeccably.

2009, Susanna Zaraysky, Language Is Music, page 19