The Spanish word 'ascetismo' (meaning 'asceticism') traces back to Ancient Greek roots. It starts with the Greek verb 'ἀσκεῖν' (askein), which meant 'to work, exercise, or practice.' From this verb came the Greek noun 'ἀσκητής' (asketes), meaning 'one who practices or exercises.' This entered Spanish as 'asceta' (meaning 'ascetic'), and when combined with the Spanish suffix '-ismo' (which forms nouns denoting doctrines or practices), it created 'ascetismo' - the practice or doctrine of ascetic living.

A simpler related Spanish word is 'asceta', which refers to a person who practices asceticism or leads an austere, self-disciplined life. This is the base word from which 'ascetismo' was formed by adding the suffix '-ismo'.

English speakers might recognize the connection to words like 'ascetic' and 'asceticism', which come from the same Greek roots. Just as in Spanish, these English words maintain the original Greek concept of practice and exercise, though specifically in the context of self-discipline and austere living. The English suffix '-ism' (comparable to Spanish '-ismo') similarly creates the abstract noun describing the practice or doctrine.