'non-respondent' originates from Latin and Medieval Latin/Old French elements: specifically the prefix 'non' (from Latin 'non') meaning 'not', and 'respondent' from Latin 'respondēre' (past participle stem 'respondent-') meaning 'to answer' or 'to reply'.

'respondēre' in Latin developed into Old French/Medieval Latin forms (e.g. Old French 'respondre' / Medieval Latin 'respondere'), then into Middle English forms such as 'responden' and later the agentive English form 'respondent'; attaching the prefix 'non-' produced 'non-respondent', and its plural became 'non-respondents'.

Initially, the root 'respondēre' meant 'to answer' or 'to pledge a response'; over time 'respondent' came to mean 'one who answers', and with the negative prefix 'non-' it evolved to mean 'one who does not answer' — the modern sense of 'non-respondent'.