Traveller cheated one with short change? (7)

I believe the answer is:

didicoi

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'traveller' is the definition.
(I've seen this before)

'cheated one with short change?' is the wordplay.
'cheated' becomes 'did' (do can mean to cheat or trick).
'one' becomes 'ioi' (I can't justify this - if you can you should believe this answer much more).
'with' means one lot of letters goes inside another.
'short' suggests taking the first letters.
The initial letter of 'change' is 'c'.
'ioi' enclosing 'c' is 'icoi'.
'did'+'icoi'='DIDICOI'

Can you help me to learn more?

(Other definitions for didicoi that I've seen before include "Traveller" , "tinker?" .)

I've seen this clue in The Times.

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