adj.
Relating to, constituting, or involving treason: Espionage is a treasonable act.
treasonably trea'son·a·bly adv.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
