The word "kinsperson" refers to a family member or a relative, but what are some antonyms for this term? Non-relative, outsider, foe, adversary, stranger, opponent, antagonist, and rival are some antonyms for kinsperson. Non-relative refers to someone who is not related by blood or marriage. An outsider is someone who is not part of the family or community. A foe is an enemy who is opposed to a kinsperson. An adversary is someone who is in opposition or conflict with a kinsperson. A stranger is someone who is not familiar or connected to a kinsperson. An opponent, antagonist, and rival are competitors who challenge or oppose a kinsperson.