'roadless' is formed in Modern English by combining the noun 'road' with the suffix '-less', where 'road' meant 'way or path' and '-less' meant 'without'.

'road' originates from Old English 'rād' (meaning 'ride, journey'), which developed into Middle English forms such as 'rod'/'rode' and eventually the modern English 'road'; the suffix '-less' comes from Old English '-lēas'. 'road' + '-less' produced 'roadless' in later English.

Originally 'road' related to 'a ride' or 'the act of riding' and later shifted to mean a 'way or path'; the compound 'roadless' has meant 'without roads' since its formation and has retained that basic meaning.