Definition of "baneful" [bane•ful]

• Causing harm, ruin, or death; harmful. See Usage Note at baleful. (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.

• "Yesterday, Agricola made me read an article in a newspaper, in which violent blame and bitter irony are by turns employed, to attack what they call the baneful tendencies of some of the lower orders, to improve themselves, to write, to read the poets, and sometimes to make verses."
• "That man Clarke has some kind of baneful influence over her."
• "Of all the cankers of human happiness, none corrodes it with so silent, yet so baneful a tooth, as indolence."