Virāga: 'disillusion' or 'fading away', detachment; absence of lust, dispassionateness. Appears frequently together with nirodha 'cessation' 1 as a name for Nibbāna, 2 in the contemplations a forming the 4th tetrad in the exercises in awareness or mindfulness of breathing see: ānāpānasati 14, b of the 18 principal insights.
According to Com., it may mean 1 the momentary destruction of phenomena, or 2 the ultimate 'fading away', i.e. Nibbana. In the aforementioned two contemplations, it means the understanding of both, and the path attained by such understanding.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.