'mobility-retaining' is a compound formed from the noun 'mobility' and the present-participial adjective-forming element 'retaining'. 'mobility' originates from Latin 'mobilitas', where 'mobilis' meant 'movable'; 'retain' originates from Latin 'retinere', where 're-' meant 'back' or 'again' and 'tenere' meant 'to hold'.

'mobility' came into English via Latin 'mobilitas' and Old French 'mobilite', becoming Middle English 'mobilite' and modern English 'mobility'. 'retain' developed from Latin 'retinere' through Old French 'retenir' into Middle English 'retain' and formed participial/adjectival compounds like 'retaining'. The compound 'mobility-retaining' is a modern English formation combining these elements.

Initially, 'mobility' meant 'the quality of being movable' and 'retain' meant 'to hold back or keep'; the compound came to mean 'keeping the ability to move' or 'preserving mobility' in modern technical usage.