(as) stiff as a poker American simile
Used to describe people's physical manner and posture.
Used to describe someone's physical posture or demeanor very straight or inflexible
It's not easy for her to be a ballet dancer because she's as stiff as a poker.
In the progress check meeting, almost employees sit as stiff as a poker and listened to the manager’s complaint.
A rude phrase expressing contempt, disgust, or anger to someone who has a rigid or serious demeanor
To stand still, to be unbending, immutable and a little bit odd.
To be rigid and unwilling to change one's habits, behaviors, opinions, etc.
Someone who is pretentious and stuffy.
1. To be rigid in one's attitudes, looks, behaviors or opinions.
2. To be bad-tempered, hostile or serious.
If someone has a cast iron stomach, they have a strong stomach that can digest unusual food and even bad food without being ill.
Jimmy must have a cast-iron stomach, when he drank milk with lime juice and felt perfectly fine afterward.