Real Dictionary

ramrod
If someone has a ramrod back or way of standing, they have a very straight back and hold themselves in a rather stiff and formal way.
countable noun: A ramrod is a long, thin rod which can be used for pushing something into a narrow tube. Ramrods were used, for example, for forcing an explosive substance down the barrel of an old-fashioned gun, or for cleaning the barrel of a gun.

ramrod in American English
a rod used for ramming down the charge in a gun that is loaded through the muzzle
to push, direct, or manage in a rigid or unyielding way
noun: a rod for ramming down the charge of a muzzle-loading firearm
transitive verb: to exert discipline and authority on

ramrod in British English
noun: a rod for cleaning the barrel of a rifle or other small firearms