The idiom out and out means (1) thoroughly, completely, or openly; and (2) thorough, complete, or open. As an adverb, it goes back several hundreds of years—appearing, for instance, in a poem by Chaucer (“For out and out he is the worthiest”)—and its meaning has remained more or less unchanged over the centuries. The earliest examples of its use as an adjective are from the early 19th century.
As a phrasal adjective, out and out is hyphenated (out-and-out) when it precedes what it modifies (e.g., an out-and-out disaster). The hyphens are unnecessary when out and out functions adverbially.
Examples
As an adverb
The Sox need someone to out and out dominate the opposition. [Boston Globe]
We shall certainly resist out and out any attempt for an Army and Navy being set up in Ireland. [Irish Times]
THQ out and out invents a new way to use the tried and true. [Toronto Star]
As an adjective
And that kind of lending, plus out-and-out piracy, are both already fairly well priced-in. [Wired]
There are not many out-and-out Thatcherites in the present Government. [Independent]
What napping lacks in terms of out-and-out cardio health, it more than compensates for. [New Zealand Herald]