Substantial means of considerable size or importance, solidly built, ample, or well-to-do. Substantive means of or relating to substance, where substance means meaning. So substantive is often synonymous with meaningful, while substantial is usually synonymous with large.
Examples
These writers demonstrate a few appropriate uses for substantive:
Richmond blames term limits for nurturing an atmosphere dominated by spin and talking points over substantive debate and the soaring oratory of decades past. [Miami Herald]
And that’s what’s interesting about the divide: It is as much stylistic as it is substantive. [Los Angeles Times]
This is a pretty substantive pact involving two treaties, one on joint military exercises and defence procurement, the other on nuclear co-operation. [Financial Times]
The substantive objection to raising taxes is that it might slow the still sluggish economic recovery. [The New Republic]
These examples demonstrate some of the broader uses of substantial:
That’s a no-brainer; it’s a smart plan with substantial community support. [Dallas Morning News]
The married banker, paid a substantial six figure sum, began the illicit affair before the credit crunch erupted and plunged the country into recession. [The Sun]
A seven-year-long period without substantial rainfall, along with two decades of conflict, have put the African country on the brink of a catastrophe … [Toronto Sun]
