1640s, "practicing rigorous self-denial as a religious exercise," from Latinized form of Greek asketikos "rigorously self-disciplined, laborious," from asketes "monk, hermit," earlier "skilled worker, one who practices an art or trade," especially "athlete, one in training for the arena," from askein "to exercise, train," especially "to train for athletic competition, practice gymnastics, exercise," perhaps originally "to fashion material, embellish or refine material."
The Greek word was applied by the stoics to the controlling of the appetites and passions as the path to virtue and was picked up from them by the early Christians. Figurative sense of "unduly strict or austere" also is from 1640s. Related: Ascetical (1610s).
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
Others are reading
Definitions of asceticism
the doctrine that through renunciation of worldly pleasures it is possible to achieve a high spiritual or intellectual state;
the trait of great self-denial (especially refraining from worldly pleasures);