Even without Chomsky it's snug (4)

I believe the answer is:

cosy

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'it's snug' is the definition.
(synonyms)

I don't understand how the rest of the clue works.

(Other definitions for cosy that I've seen before include "Comfy and snug" , "Warm and comfortable" , "With a feeling of comfort and warmth" , "Warm and snug" , "Warm, secure" .)

I've seen this clue in the Sydney Morning Herald.

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