redoubt

Short definition from Wiktionary

Noun

1. 1
   A small, temporary, military fortification.
2. 2
   A reinforced refuge; a fort.
3. 3
   A place of safety or refuge.
4. 4
   The return of doubt.

Verb

1. 1
   To fortify, to make into a stronghold.
2. 2
   To dread.
3. 3
   To doubt again.