Audacity, n.
1. Daring spirit, resolution, or confidence; venturesomeness. The freedom and audacity necessary in the commerce of men. Tatler.
2. Reckless daring; presumptuous impudence; -- implying a contempt of law or moral restraints. With the most arrogant audacity. Joye.
Shades of meaning
Fernald has no entry of its own for audacity; he lists it under effrontery, temerity.
Where he writes about it:
Audacity, in the sense here considered, is a reckless defiance of law, decency, public opinion, or personal rights, claims, or views, approaching the meaning of impudence or shamelessness, but always carrying the thought of the personal risk that one disregards in such defiance; the merely impudent or shameless person may take no thought of consequences; the audacious person recognizes and recklessly braves them. — from effrontery
Effrontery (L. effrons, barefaced, shameless) adds to audacity and hardihood the special element of defiance of considerations of propriety, duty, and respect for others, yet not to the extent implied in impudence or shamelessness. — from effrontery
We say it is amazing that one should have had the temerity to make a statement which could be readily proved a falsehood, or to make an unworthy proposal to one sure to resent it; in such use temerity is often closely allied to hardihood, audacity, or presumption. — from temerity
Audacity, in the sense here considered, denotes a dashing and somewhat reckless courage, in defiance of conventionalities, or of other men's opinions, or of what would be deemed probable consequences; as, the audacity of a successful financier. — from temerity