1. in a way that relates to the essential nature or most important aspects of something
2. in a way that has real importance, value, or effect
3. relating to matters of substance rather than procedure or form
Usage: legal; formal

Examples

• The new policy differs substantively from the previous one.
• Her research contributed substantively to our understanding of the disease.
• The court ruled substantively on the merits of the case.
• The budget has not changed substantively since last year.
• The two proposals are substantively similar despite different wording.
• The committee focused substantively on the core issues rather than minor details.