Invariably somewhat severe? (4)

I believe the answer is:

ever

'invariably' is the definition.
(thesaurus)

'somewhat severe?' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'EVER' can be found hidden inside 'severe'.

(Other definitions for ever that I've seen before include "At all times, always" , "Veer away endlessly" , "Continually" , "On any occasion" , "Always and permanent" .)

I've seen this clue in the Evening Standard.

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