In his book, Living with the Himalayan Masters, Swami Rama (a Spiritual mentor, practitioner, Guide and a mystic from Uttarakand), shares this definition of Enlightenment, quoting a Mystic ascetic saint roaming in the uninhabited region in the vicinity of Amarnath Shrine in Jammu & Kashmir,
When Swami Rama asked the Ascetic the Highest level of Enlightenment. The mystic quoted a mantra from Upanishada, and explained the Enlightenment in the following terms,
When the sensory feelings or emotions emanating from the sense organs are eradicated from the mind by controlling the Sense organs, so that the attractive imagery of sensory bliss stops forming in the subconsciousness, then one can say that he/she has attained the enlightenment. When such a state is reached then the Mind/Consciousnesses & subconsciousness reaches the point of concentration. In such a state the mind signals emanating from Sub-conscious mind (which is not in control of our consciousness) cease, and the person stops having sensory imagery even unconsciously. This is the Highest State of Enlightenment.
Page 311, Living with the Himalyan Masters (In Hindi — Himalaya Ke Santon Ke Sang Niwas),