Definition of "shadowbox" []

• To spar with an imaginary opponent, as for exercise or training purposes. (verb-intransitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "I'm assuming it's permanently mounted in the "shadowbox," so no one can get stabbed by it...but what an odd thing to memorialize from this film."
• "I stopped in front of the last item on the wall; a sizable shadowbox."
• "I was surprised that the place was half-full, permitting one bouncer the space and lack of supervision to shadowbox."