Hello Jamil, It could be as well due to 'pragmatics', which refers to the ability of using the natural language to convey more than what is explicitly stated.This engages as well the historical development of language. Sociolinguistics contribute to changing the sense and meaning of the same word due to change in cultural norms and expectations,while pragmatics instantly change the perception of a word or concept, where almost every aspect of language including semantics and syntactics functionally interact with pragmatics.

It is just how languages evolve over time. If we are talking about a living language, it takes on form with usage by any population that speaks it. There is no formal procedure and no real rules. For instance "whore" and "prostitute" basically mean the same thing. However the "whore" is considered negative and harsh - a gross insult. "Prostitute" would be considered more of an objective desription. It might be negative, but without the harshness of "whore".