Filling a gap, spicy eel pie with TV Times to digest (9)

I believe the answer is:

expletive

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'filling' is the definition.
(thesaurus)

I cannot understand how the rest of the clue works.

(Other definitions for expletive that I've seen before include "Swearword" , "Swear word" , "I expel vet with obscene exclamation" , "oath" , "Four-letter word" .)

I've seen this clue in The Telegraph.

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