What is the opposite of word ball?

There isn't a single perfect opposite for the word "ball." It depends on what aspect of "ball" you're trying to contrast:

If you're thinking about the object:

* Opposite shape: A cube or a pyramid (a ball is round)

* Opposite material: A brick or a feather (a ball can be made of many things)

If you're thinking about the activity:

* Opposite action: Sitting still, being inactive, watching, resting

* Opposite mood: Sadness, depression, seriousness (a ball is often associated with play and joy)

If you're thinking about the event:

* Opposite formality: A formal dinner, a funeral, a business meeting (a ball is usually a social event)

Without more context, it's hard to say what the *exact* opposite of "ball" is.