causing or capable of causing harm; injurious: a harmful idea; a harmful habit.

before 1000; Middle English; Old English hearmful. See harm, -ful

harmfully, adverb
harmfulness, noun
quasi-harmful, adjective
quasi-harmfully, adverb
unharmful, adjective
unharmfully, adverb

hurtful, detrimental, damaging, deleterious.

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To harmful
World English Dictionary
harmful (ˈhɑːmfʊl)
causing or tending to cause harm; injurious

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Example sentences
Every week, it seems, a new study identifies potentially harmful chemicals in
  common items.
Although many plastics are safe to reuse, some contain components that may be
  harmful to humans and the environment.
Singling out meat-eating as harmful to the environment is overly simplistic.
Commercial oven cleaners can expose you to caustic chemicals and harmful toxins
  while reducing the air quality in your home.
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature