bu·pro·pi·on (byo?o-pr??p?-?n?)n. A drug, C13H18ClNO, used in its hydrochloride form for the treatment of depression and as an aid in smoking cessation. It is a weak inhibitor of norepinephrine and dopamine reuptake in the central nervous system.[bu(tyl) + propi(ophen)on(e), a ketone (propio(nic acid) + phen(yl) + -one).]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.bupropion (bju??pr??p??n) nan antidepressant drug used to help people stop smokingCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014