Feeling of horror passes slowly (6)

I believe the answer is:

creeps

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'feeling' is the definition.
(I know that creeps is a type of fear)

I don't understand the rest of the clue.

(Other definitions for creeps that I've seen before include "''Tomorrow, and tomorrow, and tomorrow, ... in this petty pace from day to day'' (Macbeth)" , "21 [SNAKES]" , "feeling of revulsion" , "Toadies" , "Crawls silently" .)

I've seen this clue in The Globe and Mail.

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