Type of button or room (5)
I believe the answer is:
panic
'type of button or room' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for panic that I've seen before include "Lose the head, yield to fear" , "Extreme fear" , "Sudden overpowering fright" , "Sudden extreme anxiety" , "Go to pieces" .)