Blubber keeping lake's chill out (4)

I believe the answer is:

slob

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'chill out' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.

'blubber keeping lake's' is the wordplay.
'blubber' becomes 'sob' (I've seen this in another clue).
'keeping' is an insertion indicator.
'lake' becomes 'L' (geographical abbreviation).
'sob' enclosing 'l' is 'SLOB'.

Can you help me to learn more?

(Other definitions for slob that I've seen before include "Fat, idle type" , "Slovenly person (colloq.)" , "Untidy and lazy person" , "Boor" , "Unattractive person" .)

I've seen this clue in The Telegraph.

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