Adept historians always show profundity (5)

I believe the answer is:

depth

'profundity' is the definition.
(I know that profundity can be written as depth)

'adept historians always show' is the wordplay.
'show' indicates the answer is hidden within the clue.
'DEPTH' can be found hidden inside 'adept historians always'.

(Other definitions for depth that I've seen before include "Military life; vulgarly artificial" , "Deepness" , "Distance from the surface to the bottom" , "Distance downwards" , "Thoroughness" .)

I've seen this clue in the Evening Standard.

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