Spartan
Part of speech: adjective
Definition: austere, frugal or characterized by self-denial resolute in the face of danger or adversity lacking in decoration and luxury
Resolute
Part of speech: adjective
Definition: Firm, unyielding, determined. For example, she was 'resolute' in her determination to resist his romantic advances.
Example sentence: History furnishes thousands of examples of men who have seized occasions to accomplish results deemed impossible by those less resolute. Prompt decision and whole-souled action sweep the world before them.