Doesn't stand for fibs (4)

I believe the answer is:

lies

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'fibs' is the definition.
(informal term for lies)

I don't understand the remainder of the clue.

(Other definitions for lies that I've seen before include "Is prone" , "Reclines" , "False statements" , "Assumes a horizontal position" , "Wallows" .)

I've seen this clue in The Mirror.

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