'forest-destroying' is a modern compound of the noun 'forest' and the present participle 'destroying' (from 'destroy'). 'forest' originates from Old French, specifically the word 'forest', which came from Late Latin 'forestis'. 'destroy' originates from Latin 'destruere', where 'de-' meant 'away/undo' and 'struere' meant 'to build or pile up.'

'destroy' passed into English via Old French 'destruire' and Middle English forms (e.g. 'destroien'), eventually becoming modern English 'destroy'. 'forest' entered English from Old French 'forest' (from Late Latin 'forestis') and became Middle English 'forest' and the modern form.

Initially, Latin 'destruere' carried a sense of 'undoing or unbuilding'; over time the sense shifted to 'ruin' or 'break down', yielding the modern sense 'to destroy'. 'forest' originally referred to an area set aside or 'outside' (Late Latin usage) and evolved to mean 'woodland' in modern English.