The phrase "ostensibly greater" is correct and can be used in written English.
It is typically used to describe something that appears to be greater or more impressive than it actually is. Example: The company's profits were ostensibly greater this quarter, but upon closer inspection, it was revealed that the numbers were inflated due to unethical accounting practices.
Despite the ostensibly greater sophistication of Europeans about boys being boys, Britain has been showing an indiscreet curiosity about its politicians' private lives as well, sometimes with the co-operation of the politicians themselves.
The number of troops supplied by our European allies in Afghanistan has been comparatively modest, in spite of the ostensibly greater danger to them by the proximity of Al Qaeda to Europe.
The LSA measure reported here was calculated as the cosine distance between vectors representing two words in high-dimensional semantic space, with higher numbers reflecting ostensibly greater semantic or contextual relatedness (Landauer & Dumais, 1997).
But focusing on ostensibly great men of history like Lord Balfour seems like a perfect way to keep the visceral daily indignities of the occupation out of focus.
Three months after Kerouac came down from Desolation he learned that Viking would finally publish "On the Road" — ostensibly his greatest triumph, but in reality the beginning of his end.
Putin's unexpectedly calm response after indications of retaliatory aggression that would "cause serious discomfort to the American side," was ostensibly the "great move" Trump spoke of in his tweet that is now prominently "pinned" to the top of his timeline.
It is Barber's great-great-great-grandson, ostensibly a white man called Cedric, who unveils the plaque commemorating his ancestor.
The major restructuring will ostensibly give investors greater insight into how the money is being spent.
The fiscal treaty is ostensibly about imposing greater budget discipline on the Eurozone 17-nation Eurozone.
In 2005, the Chinese government set out a number of regulations that ostensibly allowed for greater freedom of religion.
It's all ostensibly for the greater good, but there's no guarantee that the company's cost-cutting measures will be enough to see them to eventual platform victory.
