'adequately-furnished' originates from the combination of 'adequate' and 'furnished'. 'Adequate' comes from Latin 'adaequatus', meaning 'equalized', and 'furnished' comes from Old French 'furnir', meaning 'to provide'.

'adequately-furnished' evolved from the combination of 'adequate' and 'furnished', which were used separately in Middle English and later combined in modern English.

Initially, 'adequate' meant 'equalized', and 'furnished' meant 'provided'. Over time, they combined to describe a state of being sufficiently equipped with furniture.