first cousin-aunt-in-law

1. The wife of one's grandparent's sibling's son.
2. The daughter of one's grandparent-in-law's sibling.

My first cousin-aunt-in-law is a good person.

first co-cousin-aunt-in-law

The daughter-in-law of one's grandparent-in-law's sibling.

My first co-cousin-aunt-in-law is a good person.