Someone who is stern is very serious and strict. Her father was stern and hard to please
Having a certain hardness or severity of nature, manner, or aspect; hard; severe; rigid; rigorous; austere; fixed; unchanging; unrelenting; hence, serious; resolute; harsh; as, a sternresolve; a stern necessity; a stern heart; a stern gaze; a stern decree
of a stern or strict bearing or demeanor; forbidding in aspect; "an austere expression"; "a stern face"