Wikipedia is not a dictionary. In any case, the link you gave shows that "disbalance" as a noun means "to cause to be unbalanced". What did John cause to be unbalanced?
I believe it is probably AE as it is in the Merriam Webster dictionary but not in the Oxford Dictionary.
At any rate you cannot use a noun like a verb, at least not in the ordinary sense.
https://www.merriam-webster.com/dictionary/disbalance
John was leaning against the railing that was [strike]
coming up to his[/strike]
only waist
high. He [strike]
disbalanced[/strike]
overbalanced and
fell[strike]
down[/strike]. If the railing had been a bit higher then he wouldn't have fallen.
As andrewg927 has pointed out "
He lost his balance" could also be used.
"Disbalance" is another example of a $5 word. When English moderators and teachers must hunt for it in AE and BE dictionaries, you know it is a rarely used word. Such words should be avoided if you want your message understood.
John was leaning against the railing that was only waist high. He overbalanced and fell. If the railing had been a bit higher then he wouldn't have fallen.
