Wiktionary
vb. (context idiomatic English) To conceal something about oneself, without the knowledge of which others cannot know one's true character or perspective.
Usage examples of "live a lie".
Wherever he might go throughout the Seven Kingdoms, he would need to live a lie, lest every man's hand be raised against him.
A man might live a lie even to his daughter, be willing to see her terribly married rather than risk a lifework that depended on complete Tryannian trust, be willing to seem half a madman-'Artemisia found her voice.
Not only was it upsetting to pull up roots and seek a new background every few years but also it grated to have to live a lie in a society where frank honesty and fair dealing were habitual with most people.
Back, perhaps, to a safer time, before I, too, had begun to live a lie, deceiving myself most of all.
A man might live a lie even to his daughter, be willing to see her terribly married rather than risk a lifework that depended on complete Tyrannian trust, be willing to seem half a madman--”.