rigid

"My teacher was uncompromising in her expectations for the class project; no late submissions were allowed. "

"The class squirmed and fidgeted in the uncomfortable new chairs."

"My grandmother has an unbending belief in the importance of daily walks, no matter the weather. "

"Late arrival to class is an unacceptable reason for missing the test. "

"The online personal for finding a book club partner was very popular among students. "

"The efficiency of the planning department is deplorable."

"The new schedule is a flexible option for students. "

"The students wear blue uniforms to school every day. "

"suspension from a hook"

"The teacher made it clear that, with a few exceptions, all students needed to complete the assignment by Friday. "

"a rigorous execution of law"

"to allow a servant his liberty;  to allow a free passage;  to allow one day for rest"