Who were the Hesychasts?
The Hesychasts of the 13th and 14th centuries were those who practiced hesychia, that is to say, “prayer and stillness” or “silence in prayer” (cf. “Be still and know that I am God”, Ps. 46:10). In fact, as was demonstrated by St. Gregory Palamas and others, the Hesychasts simply followed the age-old tradition of “calling upon the name of the Lord” (Ps. 116:13).
For further details, see my chapter, “On Becoming Theologians: Hesychia as a Prerequisite for the Encounter with God”, in The Orthodox Understanding of Salvation: “Theosis” in Scripture and Tradition (Dalton PA: 2016), pp. 189-196; and for more general information on the Hesychasts, see also my Notes in Christopher Veniamin, ed., Saint Gregory Palamas: The Homilies (Dalton PA: 2022), e.g., pp. 538, n. 53; 593-594, n. 515; 596, n. 545.