When you mistype yeah, which looks like a cowboy saying “Yee-haw!”

From STEM, an abbreviation short for "Science, Technology, Engineering and Mathematics", a STEMlord is a pejorative term for a particular kind of person who has studied in these areas at university or works in these fields who holds a pretentious, condescending attitude to anyone who has studied in any other fields, particularly the Arts and Humanities. They typically believe themselves to be more "intelligent" and "rational", while generally remaining incredibly ignorant outside of their areas of expertise and having the charisma of a rotting pig's backside.

It's like "yeah", but more l33t.

It’s a cooler way of saying yeah

A cry given out by a shell suited youth usually during or just after committing a serious crime, usually violent in nature.

you eat his ass YEHAAAA!

you eat his ass YEHAAAAAAAAA