The term 'Cause of a Big Slice' can be solved by the word 'Mishit', which is a six-letter word. A mishit is a golf shot that does not go in the intended direction, usually resulting in a large slice. A slice is a shot that curves to the right for a right-handed golfer, or to the left for a left-handed golfer. It is caused by an incorrect swing path and is one of the most common mistakes made by amateur golfers.