I think the original is correct.
This text is from: A miscellany of law texts and other materials for law students.
United states law requires the existence of a 'treaty or convention for extradition', while the extradition legislation of Great Britain applies only 'where an arrangement has been made with any foreign States'. The word 'arrangement' is arguably of wide meaning and might extend to an exchange of diplomatic correspondence concerning a particular individual, but this view has never been tested.
I think 'arguably' needs to be changed with 'arguable,' and I think 'meanings' sounds more natural to me than the singular form.
I will be grateful if you have any point in grammar to help.
The arrangement is of wide meaning. How is it of wide meaning? Arguably.
The adverb form is needed.
May I call it a sentence adverb?
The meaning of the word "arrangement" is arguably wide.
I am not a teacher.
Is the following possible?
'Arguably, the word "arrangement" is of wide meaning.'