Harmful to one's reputation; blameworthy: discreditable behavior. (adjective)
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.
Use "discreditable" in a sentence
"Whether creditable or discreditable, that is the fact."
"But they were not reticent enough to prevent the circulation of certain uneasy rumours and extravagant stories of discreditable adventures -- discreditable, that is, from the buccaneering point of view -- of which Captain Blood had been guilty."
"It might be called discreditable enough to move any self-respecting people to shame."