'non-forest-related' is a compound formed from the prefix 'non-' plus the noun 'forest' and the adjective 'related'. 'non-' originates from Latin, specifically the word 'non', where 'non' meant 'not'. 'forest' originates from Old French, specifically the word 'forest' (from Medieval Latin 'foresta'), where 'foresta' meant 'woodland' or 'open wood'. 'related' originates from Latin, specifically the word 'relatus', the past participle of 'referre', where 're-' meant 'again' and 'ferre' meant 'to carry'.

'non-' was borrowed into English via Old French/Anglo-Norman and became the productive negative prefix 'non-' in Middle and Modern English. 'forest' changed from Medieval Latin 'foresta' to Old French 'forest' and then entered Middle English as 'forest' with the meaning of woodland. 'related' comes from Latin 'relatus' which passed into Old French and Middle English as verbs and adjectives like 'relater'/'relaten', eventually giving Modern English 'relate' and the adjective 'related'. The compound form 'non-forest-related' is a modern English formation using the prefix and two established words.

Individually, the parts initially meant 'not' ('non-'), 'woodland' ('forest'), and 'brought/connected' ('related'); over time, as a compound the phrase came to mean 'not connected to forests' or 'pertaining to things other than forests'.