Precision in choosing words is important. Shared understanding of what words mean forms the basis of language. If we don't have that shared understanding, we can't communicate. That being said, humans are messy and inexact beings. We're prone to nuance and ambiguity. Words aren't installed in our brains directly from the OED; they accrete meaning over a period of years. No two people are ever going to definitively agree on what a word means, simply because we can't burrow into each other's heads and start rearranging things.
It's a waste of time to try to nail down a word's definition beyond any shadow of a doubt, especially when you're trying to nail it to the inside of somebody else's skull. On several occasions, I've seen what could have been a very productive discussion derailed by an intellectual death spiral where people slug it out over the exact meaning of some term. Better to agree on a provisional definition that will suit the conversation at hand and move on to discussing matters of greater substance.