unbending
Not willing to change, bend, or be flexible about something.
Unbending describes someone who refuses to change their position, compromise, or show flexibility, even when it might be wise to do so. An unbending teacher might stick rigidly to the rules without considering special circumstances. An unbending negotiator won't budge from their demands, making it hard to reach an agreement that works for everyone.
The word can describe physical stiffness too: an unbending steel rod won't flex or bend. But it's most often used for people and their attitudes. While staying firm on important principles can be admirable (an unbending commitment to honesty, for example), being unbending can also mean being unnecessarily stubborn or inflexible.
Imagine a parent with an unbending rule about bedtime who won't make an exception even on New Year's Eve, or a friend with unbending opinions who won't listen to anyone else's perspective. There's a difference between having strong convictions and being so unbending that you can't adapt when situations change.
The word carries a somewhat negative tone. We might admire someone's steadfast principles, but we criticize someone for being unbending when their rigidity causes problems or blocks reasonable solutions.