sesqui-cousin 

A child of a parent's half-sibling with the other parent’s full sibling; the relative who has with the other person only three grandparents in common, but parents are different.

My sesqui-cousin is a good person.

sesqui-cousin by Usery May 2, 2021

double-cousin 

A child of a parent's full sister with the other parent’s full brother; the relative who has with the other person only four grandparents in common, but parents are different.

My double-cousin is a good person.

double-cousin by Usery May 2, 2021

half-cousin

Parent's half-sibling's child. Has among themselves; different two parents, one grandparent in common and different three grandparents.

My half-cousin is a good person.

half-cousin by Usery May 2, 2021

sesqui-cousin 

Child of their parent’s half-sibling with the other parent’s full sibling. Has among themselves; different two parents, three grandparents in common and different one grandparent.

My sesqui-cousin is a good person.

sesqui-cousin by Usery May 2, 2021

double-cousin 

Child of their parent’s full sister with the other parent’s full brother. Has among themselves; different two parents and four grandparents in common.

My double-cousin is a good person.

double-cousin by Usery May 2, 2021

first-cousin 

Cousin or 1C:
1- Parent's full sibling's child.
2- Person who, in relation to the other person, has zero parents and two grandparents (maternal or paternal) in common.

My first-cousin is a good person.

first-cousin by Gerald128 May 15, 2021

third-cousin 

3C:
1- Parent's second-cousin's child.
2- Grandparent's first-cousin's grandchild.
3- Great-grandparent's full sibling's great-grandchild.
4- Person who, in relation to the other person, has zero parents, zero grandparents, zero great-grandparents and two great-great-grandparents in common.

My third-cousin is a good person.

third-cousin by Gerald128 May 15, 2021