Descriptivism and Prescriptivism
or
How to be Correcter in Languaging
Descriptivism is the art of reporting on how language is used, often with the subtext that the way that language is used is the way you should use it.
Prescriptivism is the art of telling people how to use language, because there are rules in place, dammit!
Obviously, there is a correct solution to this debate; allow me to monologue upon the matter.
Words are good and useful tools, and sometimes you need new tools, or to use tools in new ways. Sometimes you need a new word for a new idea, like 'quark', and sometimes you need a new word to give a new tone to an old idea, like 'cromulent'. These are fine. These are even fine in cases like hybrid words ('automobile', 'sociology'), portmanteau words ('brunch', 'ginormous'), and clumsily stolen words from other languages (all of English). Somewhat dubious but also probably okay are the use of old words for something new, like 'car' coming to mean 'automobile' or 'phone' coming to mean 'hand computer'.
But, counterpoint, words are good and useful tools, and you shouldn't use a saw to do a hammer's job; it makes the saw less effective at its primary purpose. Words that might be ambiguous in many contexts ('imply', 'literally', 'beg the question') should stick with their more precise meanings, and drop the warm fuzzy "language as pretty stickers" usages.
The difficulty arises in maintaining language as a tool to communicate between people, rather than just a tool to talk to yourself. New words and new usages should add something to the communicative toolbox, not take meaning away. That which is added may be hard to see at first; 'car' is better than 'automobile' only in that it is short, but short is valuable. Unfortunately, sometimes what is added is just rhetoric flourishes, which is a great reason for inventing new words (e.g., 'fantabulous') and a terrible reason for setting loose floating signifiers (e.g., 'communism', 'fascism', 'justice', and most words used by pundits and politicians).
When in doubt, make a new tool that does the job right, and never pick a word that feels right because it fits the pattern of your speech -- not unless you're writing a song, or messing up a poem.