Predictable way of life, in truth (3)

I believe the answer is:

rut

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'predictable way of life' is the definition.
I can't tell whether this defines the answer.

'in truth' is the wordplay.
'in' says the answer is hidden in the clue.
'RUT' is hidden within 'truth'.

Can you help me to learn more?

(Other definitions for rut that I've seen before include "Furrow - dreary routine" , "Undeviating routine" , "Kind of groove or fixed habit" , "Groove made by wheel" , "mate" .)

I've seen this clue in The Times.

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