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