The phrase "a big substantial" is not correct and is redundant in written English.
You can use it when trying to describe something that is both large and significant, but it is better to choose one of the adjectives.
Example: "The project required a big substantial investment, which was not feasible for our budget."
Alternatives: "a significant" or "a large".
This cosmic juxtaposition of adult and child, of large and small, is replicated in our vision of the toys themselves: in close-up (to use a metaphor drawn from old-fashioned spatial reality) they are big, substantial heroes, battling resourcefully with complex and considerable foes.
Asked about comments he made last year, before the pair took opposing sides in the EU referendum campaign, Cameron said: "I wouldn't withdraw any of the things I've said – the Conservative party is lucky to have big, substantial figures within it".
I mean take Obama and that big meeting he had in Latin America: what becomes the big substantial thing that we talked about is that Obama shook hands with Chavez; he had a smile on his face when he shook hands.
"And here within a relatively short time, you've become a big businessman with substantial assets across the country and in various sectors of the economy.
But, and this is a big but, a substantial but here...the Pitcairn Islands aren't quite a suntrap on the Adriatic.
"In that sense, it is a big deal, a pretty substantial departure" in American policy, said Francis Brooke, the American adviser to the London-based dissident group.
It's a big drama with a substantial cast, and a few longeurs that the later Bleasdale may not have tolerated.
Beyond violating our laws, visa overstays pose — and they really are a big problem — pose a substantial threat to national security.
If YouNoodle actually works–and that remains a big if it could drive substantial change in the venture capital industry.
Federal officials say that if a tanker were aimed at a big bridge or building, substantial damage and many deaths could result.
