"condescending smile" is correct and can be used in written English.
It is usually used to describe an expression or gesture that conveys a feeling of superiority or judgment. For example: The teacher addressed the student with a condescending smile, as if to remind her that her efforts were not good enough.
I was also a little upset at Mr. Obama's condescending smile, all the time acting as if he was so much smarter.
When addressed, they perked up their ears & regarded writer warily & without a trace of the condescending smile that a professor gets on his face just before he says, "Good point".
Despite his dehumanisation, however, Agu achieves a kind of insight into himself when he is finally questioned by a kindly, well-meaning teacher, whose bland condescending smile betrays her lack of understanding about what he has gone through: "I am not a baby – I am an old man and she is a small girl".
Barbie entered the scene like a powerful gust of resentful wind, with a condescending smile on her face.
"It's hilarious to me on one hand, and on the other hand I remember the Bush/Kerry election and the Bush/Gore election and it wipes the condescending smile off my face.
My name is finally called and I run into the room with a huge condescending smile on my face.
Behind Shaun T, a gaggle of spandexed, generic-looking fitness types bust a professional move with faintly condescending smiles pasted on their faces, as if they're not dancing so much as spooning Geritol-laced pudding into your mouth.
His explanations were met with condescending smiles.
It wasn't an unfriendly smile, exactly, not cruel or condescending.
Chaney called the lyrics "condescending", and found the juxtaposition of the singers' smiling faces and the phrase "clanging chimes of doom" to be "weird".
New research suggests that women consider condescending remarks less offensive when men in an authoritative stance deliver them with a smile and some macho body language.
