Adharma: Unrighteousness; demerit, failure to perform one’s proper duty; unrighteous action; lawlessness; absence of virtue; all that is contrary to righteousness (dharma). (A Brief Sanskrit Glossary)
Dharma: The righteous way of living, as enjoined by the sacred scriptures and the spiritually illumined; law; lawfulness; virtue; righteousness; norm. (A Brief Sanskrit Glossary)
To be truly human is to be awakened enough to knew what is dharma and what is adharma and to hold to dharma and eschew adharma. That is why in the Yoga Sutras yama and niyama, the principles of right thought and deed, are the first step of yoga. And those who do not take the first step cannot really take any others, though a lot of people are fooling themselves about that fact.
Without a clear awareness of dharma and adharma, and a life perfectly conformed to dharma, we are not truly human. But those who know the distinction and live according to dharma are truly human beings.
The state of liberation is the sole virtue. All other lesser virtues lead to that. All the powers of the individual must become united through yoga and manifest that unity.
Next in Living the Yoga Life: Yoga–The Supreme Dharma