The Spanish word 'irrepetible' (meaning 'unrepeatable') is built from several Latin components. It starts with the Latin verb 'petere' meaning 'to seek' or 'to request'. This was combined with the prefix 're-' (meaning 'again') and the suffix '-ibilis' (meaning 'able to be') to form the Latin word 'repetibilis' meaning 'repeatable'. This evolved into the Spanish word 'repetible', and finally the negative prefix 'in-' (which becomes 'ir-' before words beginning with 'r') was added to create 'irrepetible', literally meaning 'not repeatable'.

This word formation shows how Spanish inherited Latin's rich system of prefixes and suffixes to create new words with modified meanings.

Some simpler related Spanish words include 'pedir' (to ask for, request), 'repetir' (to repeat), and 'repetición' (repetition). All these words share the Latin root 'petere'. While 'pedir' maintained the basic meaning of requesting or asking for something, 'repetir' and its derivatives incorporate the idea of doing something again, as indicated by the 're-' prefix.

English speakers might recognize the connection to words like 'repeat', 'repetition', and 'repetitive', which all come from the same Latin source. The word 'petition' (a formal request) is also related, coming directly from the Latin 'petere'. The prefix 'ir-' in 'irrepetible' works the same way as in English words like 'irregular' or 'irreversible', meaning 'not'.