fastness[noun]Synonyms: fort, citadel, fortress, redoubt, stronghold
Related Words: retreat,
shelter,
defense,
guard,
protection,
adytum,
sanctum [TahlilGaran] English Synonym Dictionary ▲
fast‧ness /ˈfɑːstnəs, ˈfɑːstnɪs $ ˈfæst-/
noun [countable] literary a place that is safe because it is difficult to reach
Synonym : stronghold:
mountain fastnesses [TahlilGaran] Dictionary of Contemporary English ▲