If a cricket ball pitches outside off stump, but then turns so sharply that it misses leg stump, is it is a wide ball or not?
In the laws of cricket a wide is defined as a ball that a batsmen cannot play a normal cricket shot too. See Law 25 Wide Ball.
That is the basis for judging whether a ball is wide in cricket where there are not playing conditions relating to the wide ball.
Most limited overs cricket will have some variation of leg side wides, where balls passing to the leg side of the batsmen and stumps are liable to be called wide. However the exact wording will depend on the competition.
One day international Playing Conditions and T20 playing conditions are examples of this as are the ECB generic conditions
So to answer the question, under the laws of cricket the ball is probably not a wide, under the playing conditions of one day cricket it is likely to be a wide.