Grin or smirk
smirk
Smiling, beaming
smile, smirk
Smirk is one alternative.
The suffix "-y" can be added to "smirk" to create the word "smirky." This suffix is used to describe someone who often wears a smirk on their face.
The word smirk is a noun meaning sly smile. Synonyms for the word smirk include beam, grin, leer, simper, grimace, grim, sneer, visage, and smug look.
smirk
The prefix of the word "smirk" is "sm-" which means a slight curling of the lip, often indicating amusement or smugness.
Conquettish mean fake or phony. Sometimes it can be used as another word for sarcastic. Example: She put on a conquettish smirk.
Josh had a smirk on his face when he got a B+ on his test.
perhaps "grimace"