Clever person that set this up on time (4)

I believe the answer is:

deft

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'clever person that' is the definition.
'deft' can be an answer for 'clever' (deft means skilful or clever). I am not sure about the rest of the definition.

'set this up on time' is the wordplay.
'set' becomes 'fed' (I am not sure about this - if you are sure you should believe this answer much more).
'this up' is a reversal indicator (in down clue: letters go upwards).
'on' means one lot of letters go next to another.
'time' becomes 't' (abbreviation).
'fed' backwards is 'def'.
'def'+'t'='DEFT'

Can you help me to learn more?

(Other definitions for deft that I've seen before include "Quick and skilfull" , "Dextrous" , "Nimble-fingered" , "Skilful, handling things easily" , "Adroit, skilful" .)

I've seen this clue in The Guardian.

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