'avidness' originates from English, specifically formed from the adjective 'avid' plus the suffix '-ness', where 'avid' ultimately comes from Latin 'avidus' meaning 'eager' or 'desirous'.

'avid' changed from Latin 'avidus' (meaning 'eager, greedy') into English (borrowed via Late Latin/Modern usage) as 'avid' in the late 16th century, and 'avidness' was later formed in English by adding the nominalizing suffix '-ness'.

Initially related to the Latin sense of being 'eager' or 'desirous', it evolved in English to express the state or quality of eager enthusiasm — now 'avidness' (and its plural) means intense eagerness or enthusiasm.