C is A’s father’s nephew. D is A’s cousin but not the brother of C. How is D related to C ?

In this diagram, A is the person who is asking the question. B is A’s father. C is A’s father’s nephew. D is A’s cousin.

C is related to D through their shared grandfather. C’s grandfather is A’s father. D’s grandfather is also A’s father. This means that C and D are first cousins once removed.

Aunt is a female relative of a person’s parent, usually the sister of the father or mother. In this case, D is C’s aunt because she is the sister of C’s father.