A "blunt tool" refers to something that is not effective or efficient in achieving a desired outcome. It implies that the tool lacks precision or finesse, making it less impactful or successful in its use. Full definition
But even this might be too blunt a tool for our future energy needs. (theconversation.com)
It is a somewhat more blunt tool in comparison to open - market operations, since it influences many financial institutions at the same time. (wikinvest.com)
And Russell Hobby, general secretary of the National Association of Head Teachers, said the «blunt tool of inspection» was not an effective way to drive improvement in careers guidance. (bbc.co.uk)