Jargon uncovered over time? (5)

I believe the answer is:

argot

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'jargon' is the definition.
(argot can mean jargon or slang)

'uncovered over time?' is the wordplay.
'uncovered over' becomes 'argo' (I can't justify this - if you can you should believe this answer much more).
'time?' becomes 't' (abbreviation).
'argo'+'t'='ARGOT'

Can you help me to learn more?

(Other definitions for argot that I've seen before include "Particular group's jargon" , "Patois for groat" , "Groat (anag)" , "Slang, patois" , "Cant" .)

I've seen this clue in The Times.

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