WordNet Dictionary- [adj] erect in posture; "behind him sat old man Arthur; he was straight with something angry in his attitude"; "stood defiantly with unbowed back"
- [adj] not forced to bow down to a conqueror
Webster's 1913 Dictionary\Un*bowed"\, a. [Pref. un- not + bowed.] Not bent or arched; not bowed down. --Byron.