2nd cousin, but if it's your Dad's 2nd cousin... then your relationship with that cousin would be a 3rd cousin.
He would be your second cousin.
Your father's first cousin's son is your second cousin. Your father's second cousin's son is your third cousin. If your are asking about your fathers cousins who are in a removed cousin relationship to your father, their relationship to you be more complex, with two different possibilities in each case.
2nd cousin
not really
A cousin.
your cousin.
The relationship between you and your cousin's spouse is that of a cousin-in-law.
It depends on if you share a common ancestor. If not, there is no relationship.
Second couins
Maybe. O.O
niece in-law
Your grandfather's cousin is your cousin twice removed. Her husband has no direct relationship to you.