This is In character ONLY. If your character saw them on the battefield or a neutral zone or something. If your character wanted to insult the character above what would he or she say. Hold nothing back.
For example:
You are truly are a hideous Orc. I’ve heard tales of your grotesque acts throughout Azeroth.
I hate you damn elves. You are truly the most coldest of all of them.
throws soap at and says nothing
I’ve never seen such a puny throw from a troll in my life. Here I go thinking they were the best axe throwers. This troll cannot even toss a soap.
You look almost as hideous as the humans you steal your outfit from.
Yo buddy! I hear yer birth certificate was an apology letter from yer uncle!
I can’t insult Kopperschott. He’s my friend :C
Be gone… THOKK!
I don’t like insulting people but if you insist…
“Woah… somebody’s wayyyyy past their expiration date. How about you go and become fertilizer for some trees or something?”
this rogue’s mother was a hamster and their father smelt of elderberries!
Zandalari. First you built a failed empire, then you tried to suck up to the Thunder King because you were afraid a few little quakes meant your island was sinking, and now you come crawling to the Horde. Imagine failing your empire so hard that you join two other failed empires, and cause their ultimate chaotic collapse as well.
Pathetic.
(Crazy thing is, Fal doesn’t even hate the Horde. Just the Zandalari. Fought on the Isle of Thunder and trusts them as far as he can kick them 
)
picks ear for a moment Sorry, I don’t be speaking non-sentient monster.
(Loh fully knows Velves are sentient. He just regards them veeeery lowly and he’s made a comment like that to a velf who got uppity ICly)
Looks up at the previous poster. Immediately shakes his head and sighs.
“I’m too old for these games you kids play, these days. I’m going back to my library.”
You orcs are primitive beast who has slain many of my people. Reading books will do you no good. You should be off swinging a axe at an alliance. Filthy orc.
“What the hell are you wearing?”
“Wait, ya boyfriend is four thousand years old? What they hell are ya doing dating a man half your age!?”
“Some parts certainly didn’t grow back larger.”
“Sunsong. Go frolick and skip through a meadow.”
“I could bet ten mana-shards on this. You are the worst hunter in all of Azeroth. You couldn’t kill a crocolisk with a bow even if it sat on you!”
“At least I don’t have a crippling mana addiction you fiend.”