counterarm noun 3verb 1forms 3 noun3 •A weighted arm, or an arm that holds a weight, which acts as a counterbalance.Balancing this at the other end of the teeterboard was a counterarm. — 1939 •A weapon that is acquired in order to counter one held by an opponent.The submarine is the dominating weapon today. Undersea boats spell a nameless, historical terror because no effective counterarm has been perfected. — 1917 •A galactic arm on the far side of a galaxy that is colliding with another galaxy.On the far side of the larger galaxy a counterarm sometimes sprouts out. — 1978 verb1 •To arm oneself in order to match the level of weaponry held by an opponent.The lesson of the last four years is therefore that the zero option would not now be within our grasp if we had not taken the decision to counterarm and restore parity. — 1987 formscounterarmed · counterarming · counterarms