spiv

[Metz]

where does it come from,what does it mean ?

[jno]

someone living on the fringe of legality (it was especially used of black marketeers in the second world war.) Probably a Romany word.

[Quizmonster]

The Oxford English Dictionary suggests that - though the origin is obscure - it is a variant of 'spiff', which meant to dress up, and the adjective 'spiffy', meaning "dressed up to the nines", as it were.
A key feature of the spivs in the 1930s/1940s was the flashy and expensive way they dressed compared with the drab way most other men appeared. They could do that because they had lots of money from their blackmarket dealings.

[rescuer]

I thought that it was from VIPs (very important persons) and this was reversed to refer to those who were far from being important.