a blunt object used as a weapon
cudgel - club
The original use of the term ‘cudgel’ was to describe a short and heavy stick or club that a person could use for either attack or defence. While it can still be applied in that way, it is now much more commonly used in reference to employing something to attack somebody or something else in a figurative way.
The minister accused the opposition party of using the ongoing crisis as a political cudgel to attack the government.
Rather than simply striving to be better, that company uses its financial muscle to cudgel the opposition into submission.
Sanctions are often employed by the international community as an economic cudgel to punish rogue nations or to try to bring them back into line.