Noun
(literally) An object lacking sharp surfaces, especially as used to cause injury.
(figuratively) A thing, person, method, or resource which is not sufficiently precise or not sufficiently effective for its intended role or use.
Source: en.wiktionary.orgI wanted to take up music, so my father bought me a blunt instrument. He told me to knock myself out. Jay London
You have to have a certain realism that government is a pretty blunt instrument and without the constant attention of highly qualified people with the right metrics, it will fall into not doing things very well. Bill Gates
A boycott is, inherently, a blunt instrument. It is an imperfect weapon, a carpet bomb, when all involved would prefer a surgical strike. Conor Oberst
The past is a life sentence, a blunt instrument aimed at tomorrow. Claudia Rankine
Chemotherapy is just medieval. It's such a blunt instrument. We're going to look back on it like we do the dark ages. Eric Topol
The clock, for all its precision in measurement, is a blunt instrument for the psyche and for society. Schedules can replace sensitivity to the mood of a moment, clock time can ride roughshod over the emotions of individuals. Jay Griffiths