Honkin'.

I was in the local grocery store yesterday and a woman, approximately 50 years old, was with a young child (a son, or a grandson, it's hard to say).

As I wheeled my shopping cart past the pair, I heard the woman say to the youth, "We need that big honkin one."

I was probably as young as that child the last time I heard that term "honkin" in such a way. What does it mean? Where does the expression come from? (Bonus points, Kootch?)