Of those three, "blunt instrument" is definitely the most common. I said that from my own knowledge of English. Now I am going to verify it. Here's a way you can do this for yourself. Do a Google search on each phrase and see how many hits you get. Put the phrase within quotation marks. I think it's better to do the search on Google Books then simply to do it on the whole web, because Google Books means you are getting "good English" as printed in books. "blunt movement" About 65 results "blunt proposition" About 699 results "blunt instrument" About 199,000 results You do have to be a little careful, though, as "Blunt" can be a surname and the hits contain a certain number of phrases like "Mr. Blunt's proposition." However, with a difference like 699 versus 199,000, I think we have our answer! A "blunt instrument" means a tool, or an object used as a tool, that isn't sharp. A knife is a sharp instrument. A hammer is a blunt instrument. The phrase actually comes from legal, police, or medical terminology. If someone comes to the emergency room, unconscious, with a fractured skull, the doctor, not knowing yet if the victim was hit with a hammer, a rock, or a club, might say "this injury was made by a blunt instrument."

I use it more often to describe straightforward answers. For example, people often say, "That was a blunt remark!" In my experience, the secondary use would be for weapons or tools that aren't sharp. The word is not commonly used to describe movements.

Blunt instrument

What was your answer?

Most common heard use: TV crime drama - blunt instrument, blunt force trauma Most common in real life: As Naomi says, like B, blunt response, blunt remark, as in "not sharp" imprecise, non-surgical, "proposition" - maybe, but not so often