1. In Hinduism, all actions that diminish the sufferings of others.
2. In Buddhism compassion is a virtue which is of importance in all schools but which is particularly emphasized in Mahāyāna. In early Buddhism, karuṇā figures as one of the four ‘Sublime Attitudes’, namely love or benevolence (metta), compassion (karuṇā), sympathetic joy (mudita), and equanimity (upekkha).
In the Mahāyāna, karuṇā is emphasized as the necessary complement to wisdom (prajña) and as an essential ingredient in the perfection of the fully enlightened. Hence the bodhisattva of the Mahāyāna seeks to attain nirvāna for the benefit of all, and vows that he will not cease from his efforts until all beings have attained liberation. In Mahāyāna iconography and art the embodiment of compassion is the great bodhisattva Avalokiteśvara.
"Karuṇā." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (December 11, 2017). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/karuna
"Karuṇā." The Concise Oxford Dictionary of World Religions. . Retrieved December 11, 2017 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/karuna