noun
arms race; armaments race
Refers to a competitive buildup of military weapons and forces between nations.
冷戦時代、米ソ間で軍拡競争が激化した。
During the Cold War, the arms race between the US and the Soviet Union intensified.
軍備拡張 is a more general term for military expansion or buildup, while 軍拡競争 specifically emphasizes the competitive, race-like aspect between rivals.
Compound of 軍拡 (abbreviation of 軍備拡張, 'military expansion') and 競争 ('competition, race').