'buena' originates from Spanish, specifically the word 'bueno', which ultimately comes from Latin 'bonus' where 'bonus' meant 'good'.

'buena' changed from Latin 'bonus' (through Vulgar Latin and Old Spanish forms such as 'bono', 'buen'/'bueno') and eventually became the modern Spanish feminine form 'buena'.

Initially it meant 'good' in Latin and this basic meaning has largely been preserved into the modern Spanish 'buena' (with gender/number inflection).