Grandparent's female third cousin.
My third great-cousin-aunt is a good person.
Someone who, in relation to others, has zero parents, zero grandparents, zero great-grandparents and four great-great-grandparents in common.
Irregular-triple-third-cousin.
Living being that has zero parents, zero grandparents, zero great-grandparents and five great-great-grandparents in common with other living beings.
irregular-triple-third-cousin.