Semantic slanting is part of the art of persuasion or "spin." It is the purposeful choice of words and usages that are aimed at persuading the listener to embrace a point-of-view. In addition to basic meanings, words can also contain shades of meanings and negative or positive connotations.
In English, for instance, the words scent, aroma, odor, and stench are all references to how something smells. However, they have different slants on smell by having a connotation of whether the smell is pleasant or unpleasant or whether it is strong or delicate.
Additionally, words can also give an impression of "street level" speech or speech that is more refined and educated. Semantic slanting is heavily used in politics and advertising or anywhere else that it is necessary to use words in ways that are diplomatic or politically correct.