verb.
To act in opposition to; to hinder, defeat, or frustrate, by contrary agency or influence; as, to counteract the effect of medicines; to counteract good advice.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
verb.
act in opposition to
verb.
oppose and mitigate the effects of by contrary actions
verb.
oppose or check by a counteraction
verb.
destroy property or hinder normal operations
Word Usage
"Another influence we have to counteract is that of newspaper headings and placards which catch the eye of children in the streets and appeal so powerfully to their imagination."