The phrase "a little preposterous" is correct and usable in written English.
It can be used to describe something that seems absurd or unreasonable to a small degree.
Example: "While I appreciate your creativity, I must say that your idea for a flying car powered by hamsters is a little preposterous."
Alternatives: "somewhat ridiculous" or "a bit absurd."
If that sounds a little preposterous, that's because it is.
This entire story sounds more than a little preposterous from the get-go.
More than 15 months from Iowa caucus, it may be a little preposterous to be discussing presidential contenders.
When reports started circulating, three months ago, that the Queen had decreed that the Duchess of Cambridge's hemlines should be lower, they sounded a little preposterous.
I don't want to say too much more, since while the plot may be predictable (and more than a little preposterous) in retrospect, Mr. Soderbergh handles it brilliantly, serving notice once again that he is a crackerjack genre technician.
It's unashamedly sentimental and not a little preposterous, but writer Rachel Wagstaff and composer/lyricist Richard Taylor have succeeded in transforming this ration-era fairytale into one of the most heartwarming and tear-forming British musicals of recent years.
That claim might have seemed a little less preposterous, had the band not taken to the stage after its customary fanfare: recordings of Jay-Z's "99 Problems," followed by a healthy stretch of Alan Silvestri's score for "Back to the Future".
But someone would have eventually thought of aqueducts, a 9-to-1 workday would at least sound less onerous, and a time-based thriller like "24" could be a little tighter and less preposterous.
It seemed preposterous and more than a little hubristic, but that was before I woke up a couple of days ago and read two stories about the emerging field of geo-engineering.
From the start, something has been a little off with this undertaking, beginning with its preposterous scale.
I visited an older one of these settlements, Katameya Heights, a golf resort with a little shopping village where the signs are in English and preposterous Roman villas hide behind walls of bougainvillea.
