The phrase "almost unrealistic" is correct and usable in written English.
It can be used to describe something that is very unlikely or difficult to believe, but not entirely impossible.
Example: "The plot of the movie was almost unrealistic, with its series of improbable coincidences and events."
Alternatives: "nearly unbelievable" or "practically implausible."
With O'Neal out, however, 16-0 would be an almost unrealistic chore.
"The public's perception of the expectations of him, I think, might have been almost unrealistic," Mullen said.
For teenagers today, earning minimum wage trying to save for college – that gap becomes almost unrealistic, to think that you could work a low-wage job and save enough to make a dent in the cost of your college education.
In manufacturing facilities, especially in large machining centres, it is almost unrealistic to maintain constant ambient conditions.
I think we will always worry about how we look to some degree, so it's almost unrealistic to give advice like, "Just don't worry" and "Only focus on the inside".
Sticklers may have noted that, both on the remarkably strong "That's Why God Made The Radio" album and on stage, the group's sound is rounded out to almost unrealistic proportions by their superb backing band, fundamentally the same musicians who have accompanied Brian on his triumphant tours of the past decade-plus.
Her (most unrealistic) dream is to be on Broadway and she loves chocolate almost more than life itself.
Talk about unrealistic expectations.
She said she did not believe that €315bn could be raised from €21bn, a leverage factor of 15 which the ETUC argued was "almost certainly unrealistic".
The Almost Moon is unrealistic, but it's leavened with realistic description, much as the previous novel's hard-to-swallow heaven is made semi-palatable by the ordinary community and family scrutinised from it.
It should be remembered that this is almost certainly an unrealistic scenario, and performance of any algorithm would almost always be worse than that outlined here.
