Can anyone help me finding the term for this expression

[Glebe]

Trying not to laugh with a mouth full of Starbucks coffee.

[Chedney Honks]

It's demonstrative superciliousness.

She is superior in many ways, but because of her own vulnerabilities and superficial disregard for others, she also feels the need to show that she's superior to bolster her often fragile ego. This rarely has the intended effect, and rather creates a level of mutual animosity which then motivates further demonstrative superciliousness because now she wants to punish them for their resentment. She is tormented by her own self-perception.

[Elderly Sumo Prophecy]

Also, she has a big dragon, and she's not afraid to use it.

[Cerys]

She's clearly in the process of squeezing a rather long fart through a very tight sphincter.  If you look carefully at her face, you'll be able to hear the sound - like the air escaping a balloon that has painful delusions of being an oboe.

[Magnum Valentino]

It's the particular "aw, bless" brand of patronising.

[Norton Canes]

It's a smarl

[popcorn]

Sorry if this is an annoying suggestion but, assuming this is going to be an instruction for an actor, try writing out in concrete terms what the character is feeling/expressing, rather than having them guess based on your description of the smirk.

eg:

Code Select Expand

Sarah SMIRKS, like "fuck you, I win and there's nothing you can do".

Also remember that many people don't know what the fuck supercilious means, including me.

[Sebastian Cobb]

[dex]

Ah, smug mode.