A father that is not inclined or disposed to get involved in the raising or enjoyment of his children.
If it is convenient, he will show up and participate - but he will stay on the side lines and observe mildly interested.
Friend: Did Joey's dad show up?
Me: Ya he arrived for the last 3 minutes of the playoff game, and then he grudgingly saundered over to the field. The asshole didn't even see his son play.
Friend: What a relucant father