The phrase "a bit idiotic" is correct and usable in written English.
It can be used to describe something that seems foolish or lacking in sense, often in a light-hearted or mildly critical manner.
Example: "I thought it was a great idea at the time, but looking back, it was actually a bit idiotic."
Alternatives: "somewhat foolish" or "a little silly."
His character's very recognisable, he's like a lot of your friends, who are quite funny and quite handsome but a bit idiotic.
As Claudia attempts to pump up Román's optimism, Ms. Córdoba can purr about wildly imaginative indecencies with such innocent intonation that you have to wonder whether her character is a bit idiotic.
I watched a lot of Star Trek and you have a complete philosophy of life in there, even if it's a bit idiotic and very much of its time.
One of my more original (or most likely wrong) contributions to all this idiotic speculation came through a bit of amateur sleuth-work in Sonnet 86, the most famous of the "rival poet" sonnets.
Ms. Gallagher told the young man it was idiotic to think that houses don't settle a bit in 100 years.
We realize this whole thing is all still a bit confusing, so we're here to answer all of your idiotic questions about what exactly went down.
They have always seemed a bit too Fry and Laurie for my tastes (young fogey and his slightly idiotic friend) and I couldn't bear the constantly recurring Ge Me Hennimore 1970's sitcom spoof.
If we've arrived at a place in the evolution of our culture where blatant, idiotic and utterly pointless sexism can be airily dismissed as "a bit of a laugh", then clearly we have much further to go than previously thought.
This is a bit of a story disconnect, as the new Connor4real songs aren't any less idiotic than the ones that were beloved by the stream of celebrity talking heads (Questlove, Mariah Carey, Simon Cowell).
You would pull a muscle or twist an ankle or fall off a horse on your family's idiotic dude-ranch vacation (Jews on horseback? Whose bright idea was that?) and be out of commission for a bit.
These conversations have been on my mind quite a bit in the past few days as the tired old question "Did Harper Lee really write To Kill a Mockingbird?" rears its idiotic head again amid the furore over her new/old novel Go Set A Watchmen.
