1) An unsatisfying or non-existent sexual encounter with a woman.
2) A woman who is functionally retarded in terms of sexual skills or performance.
3) The lack of available or attractive women with whom to hook-up.
"Being with her is like having sex with a Barbie Doll in a coma. Chick's a total fud dud."
Doug: How was the bar last night?
Keith: Fud dud, man. The place was a complete sausage-fest.