If something is stiff, it is not easy to bend or move. Also, if a person is stiff, their body does not move easily.
Stiff can make people think of feeling uncomfortable or sore.
Examples:
The old book's pages are stiff.
The new shoes are stiff and hurt my feet.
She walked with a stiff body.
The robot moved in a stiff way.
After exercise, my legs are stiff and sore.
The tree was so stiff, it didn't move in the wind.
A dead body is stiff and does not move.
Stiff can make people think of death or sadness.
Examples:
The stiff body was lying on the ground.
The stiff cat didn't move at all.
The stiff dog was very still.
The stiff bird didn't fly away.
The stiff fish was floating in the water.
The stiff bear didn't wake up.