3 or more words used in the Giver's society that distorts or conceals the meaning of the words we use now in order to promote the rules and conventions of the community.
It seems to me that you are asking about euphemisms contained within "The Giver." A euphemism is defined as follows:
the use of an indirect, mild, delicate, inoffensive, or vague word or expression for one thought to be coarse, sordid, or otherwise unpleasant, offensive, or blunt.
For me, the biggest euphemism in the novel is "release." Sounds nice and gentle. Almost like granting someone freedom; however, in the novel "release" means euthanasia or "mercy killing." When people in the community are deemed inadequate or unworthy, they are told that they will be released. Babies and old people are the most common. It means they are going to be killed.
"Replacement child" is another word that is distorting its hidden meaning. "The Giver's" society will grant people a "replacement child" when a previous child is "released." So replacement child not only means a second child, but it also means that the first kid was killed.
"Stirrings." This one cracks me up. It's used instead of puberty or adolescence. The word is indicating that young adults have sexual stirrings. In other words, the youth begin to have sexual thoughts and emotions.
All of these words promote the rules and conventions of the society in the novel, because the people in the novel have no experience with emotions like hate, sadness, or depression. The language itself aids in that setup, because the people simply don't use words that connote sad things.