'curviness' originates from English, specifically from the adjective 'curvy' + the suffix '-ness', where '-ness' meant 'state or quality'. 'Curvy' in turn comes from 'curve' + the adjectival suffix '-y', where '-y' meant 'characterized by'. 'Curve' ultimately traces back to Latin 'curvus' meaning 'bent'.

'curviness' was formed by adding the noun-forming suffix '-ness' to the adjective 'curvy' (a formation in modern English, late 19th to early 20th century). 'Curvy' was formed from 'curve' + '-y'. 'Curve' entered English via Middle English from Latin 'curvus'.

Initially, Latin 'curvus' meant 'bent'. Over time the root developed into the noun 'curve' meaning 'a bent line or form', then into the adjective 'curvy' meaning 'having curves', and finally into 'curviness' meaning 'the quality of having curves' or specifically 'attractive roundness'.