In thinking about your question, we might recall the conversation between Humpty Dumpty and Alice in Through the Looking Glass. At one point, Humpty Dumpty exclaims "There's glory for you." Alice protests that she doesn't know what he means.

Humpty Dumpty smiled contemptuously. "Of course you don't -- till I tell you. I meant 'there's a nice knock-down argument for you!'" "But 'glory' doesn't mean 'a nice knock-down argument'," Alice objected. "When I use a word," Humpty Dumpty said, in rather a scornful tone, "it means just what I choose it to mean -- neither more nor less." "The question is," said Alice, "whether you can make words mean so many different things." "The question is," said Humpty Dumpty, "which is to be master -- that's all."

Philosophers often distinguish between the semantic meaning of a word -- its assigned meaning in language -- and the speaker meaning of a word --what the speaker intends to mean by the word. Most of the time, if we want to communicate successfully, we need the speaker meaning of what we say to match up with the semantic meaning. If we behave like Humpty Dumpty, and our speaker meaning diverges from the semantic meaning, then our listeners will be like Alice, puzzled and uncomprehending of what we are trying to communicate. But over time, if speakers consistently use a word in a way that differs from its semantic meaning, then it does seem as if the word can thereby acquire a new semantic meaning. Language--meaning--does change with use.

This website lists many examples of semantic change, at least one of which I found disturbing:

"Philosophy is originally a science concerned with the use of reasoning and argument in the pursuit of truth and greater understanding of reality and the metaphysical. Now it has come to mean little more than ‘policy’ in a sentence like The company's philosophy is to be aggressively competitive."

Somehow, the semantic changes wrought by persistent Humpty Dumptyism seem especially troubling when it concerns one's own livelihood! (And for what its worth, those of us on AskPhilosophers are not simply policy wonks -- we here are still concerned with reasoning and argument in the pursuit of truth and greater understanding of reality.)