'acid-decomposing' originates from Modern English, specifically a compound of 'acid' and the present participle 'decomposing'. 'acid' ultimately comes from Latin, specifically the word 'acidus', where 'acid-' meant 'sour'; 'decompose' ultimately comes from Latin 'decomponere', where 'de-' meant 'apart' and 'componere' meant 'to put together/compose'.

'decompose' changed from Latin 'decomponere' through Old French and Middle English forms (e.g. Middle English 'decomposen') and eventually became the modern English 'decompose' and its participle 'decomposing'; 'acid' entered English via Old French from Latin 'acidus', and the compound construction 'acid-decomposing' is a modern technical formation.

Initially the component words meant 'sour' (acid) and 'to put apart' (decompose); over time the compound has been used in technical contexts to mean 'being chemically broken down by acid' in modern usage.