shudder, shutter

Shudder or shudder means a sort of shaking or convulsive involuntary physical movement, from cold, fear, or horror--
A shudder ran through him when he heard the eerie creaking sound.
"It's cold", she said with a shudder.

Shutter or shutter means one of the two pieces of wood that closes over a window, or one of a decorative pair that doesn't close--
This shutter fell down, and now there is only one left hanging there. Can you fix it?
Just close one shutter, and we'll have some light from the open one.

Shutter or shutter may also mean the part of a camera that opens and closes, to admit light and expose the film--
You might be able to catch a picture of the dog running if you use a faster shutter speed.

Now that you know that, you can say--
"A shudder ran through me when I heard the groaning sound, but it was only the wind blowing the shutter."

Note--Not to be confused with "shut her" meaning close ( shut ) [something] belonging to a female ( her )--
Tell her to shut her mouth.
She shut her hand in the door.