a place that is thought to be safe because it is difficult to get to or easy to defend synonym stronghold要塞;堡垒 a mountain fastness 山寨。 The enemy retreated to their fastness in the mountains. 敌人撤退到他们在山里的据点。
Oxford Collocations DictionaryFastness is used after these nouns:- mountain
Word OriginOld English fæstnes (see fast ‘quick’ and -ness).