Shadowboxing

[Renato]

When a person punches in [motion] at nothing [particular], preparing for a fight or physical [fitness].

[Tracie Lynn]

The activity of sparring with an imaginary opponent as a form of training.

[Jessica]

Original: [Shadowboxing] is an exercise used in the training for combat sports, especially, as its name implies, in boxing. It is used mainly to prepare the muscles before the person training engages in stronger [physical activity]. In [shadowboxing], only one person is required to take part; the participant throws punches into the air at no one in particular or an imaginary opponent.

Slang: The act of being [evasive], vague or non-forthcoming with information.