It's sheer nonsense taking time off (6)

I believe the answer is:

rotten

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'it's sheer' is the definition.
I can't judge whether this definition defines the answer.

'nonsense taking time off' is the wordplay.
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'taking' says to put letters next to each other.
'time off' becomes 'ten' (I've seen this in another clue. I am not sure about the 'off' bit.).
'rot'+'ten'='ROTTEN'

Can you help me to learn more?

(Other definitions for rotten that I've seen before include "Corrupt; very bad" , "Morally despicable" , "Decaying - quite putrid" , "Something is ... in the state of Denmark (Hamlet)" , "Lousy" .)

I've seen this clue in the Evening Standard.

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