costless

the word 'costless' is a modern english formation, combining the root 'cost' with the native english suffix '-less'. the root 'cost' entered english from old french 'coster', which itself derived from latin 'constare' ('to stand together, to stand at, to cost'), a compound of 'com-' (together) and 'stare' (to stand). the underlying concept evolved from something that 'stands at' a fixed price to the general notion of expenditure or sacrifice. the suffix '-less' originates from old english '-lēas', meaning 'devoid of', which is related to the verb 'to lose'. therefore, 'costless' literally and logically means 'devoid of cost', directly conveying its modern meanings of being free or requiring no sacrifice.

Structure: cost (expense) + less (without) cost (from latin 'constare' meaning 'to stand at, to cost', via old french 'coster'; functions as the nominal/verbal root meaning 'price, expenditure'). less (from old english '-lēas', meaning 'devoid of, free from'; functions as an adjective-forming suffix denoting absence).