To determine the correct synonym for the word "consanguinity," we first need to understand its meaning. "Consanguinity" refers to the relationship between people who descend from the same ancestor, essentially indicating blood relation or kinship. Now, let's evaluate the given options:
- Illegitimate: This means not authorized by the law or not in accordance with accepted standards, and it does not relate to kinship.
- Adoptive: Referring to adoption, indicating a parent-child relationship not based on blood. Therefore, it doesn't mean consanguinity.
- Nonbiological: This specifically means not related by blood, which is the opposite of consanguinity.
- Kin: This term refers to one's family or blood relations, aligning directly with the concept of consanguinity.
Based on the meanings, the correct synonym for "consanguinity" is "Kin".