Rigorous in morals or principles; uncompromising, austere.

Severe in self-denial or self-restraint; stringently moral; characterized by abstinence or asceticism.

Austere, severe, harsh, bitter, morose.

= tetrical, adj.

Extremely strict in matters of conduct or behaviour; rigorous in self-discipline and self-restraint; austere with oneself; shunning laxity or…

Of or pertaining to the Ascetics, or to the exercise of extremely rigorous self-discipline; severely abstinent, austere.

= tetric, adj.1

= ascetic, adj. 1.