'unsyllabic' originates from the prefix 'un-' meaning 'not' and the word 'syllabic' from Greek 'sullabikos', where 'sullabe' meant 'syllable'.

'sullabikos' transformed into the Latin word 'syllabicus', and eventually became the modern English word 'syllabic'. The prefix 'un-' was added to form 'unsyllabic'.

Initially, it meant 'not forming a syllable', and this meaning has largely remained the same in modern usage.