The phrase "a substantive matter" is correct and usable in written English.
It can be used when discussing an issue or topic that is significant or important in a particular context.
Example: "The committee will focus on a substantive matter that affects the future of the organization."
Alternatives: "an important issue" or "a significant topic".
As a substantive matter, the bill was very mild; nonetheless, there were dire warnings of trade war and global economic disruption.
And, yes, most of us have had moments of inconsistency when our beliefs about a substantive matter distorted our views on process issues.
I have also concluded, as a substantive matter, that the record as it now exists demonstrates that the charitable foundation contemplated by the agreement is not sufficiently funded both to fulfill the eleemosynary purposes justifying a cy pres remedy and to assure that effectuation of the agreement would not have anti-competitive effects.
As a substantive matter, how should we think of these "reductions"?
But a good characterization of the distinction should not rule on a substantive matter in this way.
The Department's amicus brief is, as a substantive matter, disingenuous at best.
For his part, Mr. Burr should refuse to discuss any substantive matter relating to the investigation with the White House, except in the context of formal interviews the panel conducts.
It is enough to assume, however, that questions of how one is allowed to use the concept of identity effect only the care with which one should characterize these cases, not any substantive matter of fact.
As a more substantive matter, it's time to call foul on the GOP's economic theory, which justifies giving tax cuts to the rich and to corporations while driving up the debt.
This is an important substantive matter to the entire Latino community.
BOSTON — Feeling betrayed and disappointed by his star player, Yankees General Manager Brian Cashman sat in the visitors' dugout at Fenway Park on Sunday, calling Alex Rodriguez a liar and saying he no longer trusted Rodriguez enough to discuss any substantive matters with him.
