After World War I, though, the basic territorial pattern of the Balkans was set. Romania, Greece, Bulgaria, and Albania were independent countries and, with some exceptions, occupied their current borders. Today's countries of Serbia, Montenegro, and Macedonia were then part of Yugoslavia--a new country formed in 1918.
verb (used with object), undermined, undermining. 1. to injure or destroy by insidious activity or imperceptible stages, sometimes tending toward a sudden dramatic effect. 2. to attack by indirect, secret, or underhand means; attempt to subvert by stealth. 3. to make an excavation under; dig or tunnel beneath, as a military stronghold.
: to make (someone or something) weaker or less effective usually in a secret or gradual way. She tried to undermine my authority by complaining about me to my boss. The events of the past year have undermined people's confidence in the government.