American author regularly spooked (3)
I believe the answer is:
poe
'american author' is the definition.
(Edgar Allan Poe)
'regularly spooked' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'spooked' are 'POE'.
(Other definitions for poe that I've seen before include "Edgar Allan . . ., American writer of creepy stories" , "Edgar Allan . . ., writer of spooky tales" , "He wrote short stories" , "Edgar Allan --, US poet and author" , "The Raven writer" .)