: act against (something) : to cause (something) to have less of an effect or to have no effect at all
What made you want to look up counteract? Please tell us where you read or heard it (including the quote, if possible).
Take Our 10-Question Quiz
The commonly misspelled words quiz
How strong is your vocabulary?
The Vocab Quiz Game for iPhone & iPad
"Incredibly fun and addictive. And informative!" User Review, iTunes