The students gave a snicker when the professor came to the class in a sneaker.
snicker.....wecan say after eating snickers chocolate our laugh is supressed
he came to school with a snicker shoe , so all the students gave him a snicker / half stifled laugh
sneer+nicker ...student snickered when prof came to class with nicker (half)...so, half sneer..
snicker - when you laugh stiflingly , you get a hic hic or snick snick sound instead of a hahaha.... and hence to snicker is to laugh stiflingly or to laugh disrespectfully