'tax-averse' originates from modern English as a compound of 'tax' and 'averse'. 'tax' ultimately derives from Late Latin 'taxare' (through Old French 'taxer'), where 'taxare' meant 'to assess', and 'averse' comes from Latin 'aversus' (past participle of 'avertere'), where 'a-'/ 'ab-' meant 'away' and 'vertere' meant 'to turn'.

'tax' changed from Latin 'taxare' to Old French 'taxer' and Anglo-French forms and eventually became the modern English word 'tax'. 'averse' comes from Latin 'aversus' (from 'avertere') and entered English via Old French/Latin into Middle English before becoming the adjective 'averse'; the modern compound 'tax-averse' developed in recent English by combining these elements.

Initially, the parts meant 'to assess (tax)' and 'turned away'; combined in modern usage they evolved to mean 'reluctant to accept paying taxes' or 'inclined to avoid taxes'.