Grim (adjective) سخت، شدید، کڑا، بھیانک

very serious or gloomy.
Example: “his grim expression”
Synonyms: stern, forbidding, uninviting, unapproachable, aloof, distant, formidable, strict, dour
Antonyms: amiable, pleasant
Constrained (adjective) مجبور، روکنا

appearing forced or overly controlled.
Example: “he was acting in a constrained manner”
Synonyms: unnatural, awkward, self-conscious, mannered, artificial, wooden, stilted, strained
Antonyms: relaxed