IPA: //nɒn.rɪˈspɒn.dənt//
KK: /nɑnˈrɛspɒndənt/
A person who does not reply or respond, especially in the context of surveys or questionnaires.
The study had a high number of nonrespondents, which affected the overall results.
Nonrespondent → It is formed from "non-" (meaning not) and "respondent" (from Latin "respondere", meaning to answer). The word "nonrespondent" refers to someone who does not answer or respond.
Think of 'not' ('non-') answering ('respondere') — that's why a nonrespondent is someone who does not answer.