Nilf means Neighbour I want to fuck. People who use it probably have sexual orientation to their neighbour. But that neighbour is probably is male.
Omg here is the Nilf.
He is such a Nilf.
N. I. L. F means Neighbour I'd like to fuck. We probably have sexual feelings to our neighbour who is male. We say Nilfy for female.
He is a Nilf.
Look he is here, omg Nilf!