Byzantine monk and theologian who was the principal opponent of Hesychasm, a Greek monastic movement of contemplative prayer. He was eventually condemned for heresy.

A student of the monk-theologian Gregory Palamas (Palamas, Saint Gregory), Akindynos absorbed from him the Hesychast theory of ascetical contemplation, a method of Eastern mysticism that used repetitive formulas and mental concentration through specific bodily postures to achieve inner peace and divine union through a vision of God. The theologically conservative Akindynos at first sided with Palamas but later attempted to convince him of certain errors in the Hesychast theory.

Abetted by the accession of Emperor John V Palaeologus in 1341 and encouraged by the patriarch of Constantinople, John XII Calecas, Akindynos recorded in 1343 the history of the Hesychast dispute and by 1344 had composed seven treatises against Palamas' doctrine. Aspiring to be bishop of Thessalonica, Akindynos propagated anti-Palamite views there. In 1347, however, he was condemned by a synod after the pro-Palamas emperor John VI Cantacuzenus came to power and in 1351 was posthumously anathematized (solemnly cursed or banned) by being placed on the official list of heretics.

Akindynos' anti-Palamite letters are contained in Patrologia Graeca, edited by J.-P. Migne (1857–66).