'properly-financed' originates from English, combining the adverb 'properly' (from Latin 'proprius' via French and Middle English) and the past participle 'financed' from the verb 'finance' (from Old French 'finance' < Latin 'finis', meaning 'end, settlement'), where 'properly' meant 'in an appropriate manner' and 'finance' related to 'payment/settlement'.

'Properly' developed from Middle English 'proper' + suffix '-ly'. 'Finance' entered English via Middle French 'finance' (‘payment, settlement’), later developing the verb 'to finance' and its past participle 'financed'. The hyphenated compound 'properly-financed' became a modern attributive adjective meaning 'adequately funded'.

Initially, 'finance' pertained to payments or settlement of debts; over time it broadened to the management and provision of money. Combined with 'properly', it came to denote having appropriate or sufficient funding in place.