To laugh at someone in German is:
Jemanden auslachen
Über jemanden lachen
Yes, laughter is a noun. It refers to the sound or action of laughing.
someone - jemand
laughing = 'aka'aka
It's wrong to laugh at someone who is unhappy or distraught. There's a difference to laughing WITH someone and laughing AT someone. Laughing WITH someone is usually lighthearted fun, and nobody gets hurt. Laughing AT someone is considered rude or mean, because the person being laughed at is usually in an unhappy situation.
not really because if you smile at someone you are not laughing
Depends on how it is used. As in Santa Claus laughing (Ho! Ho! Ho!) not a bad word. But calling someone a ho as an insulting name is a bad word.
Someone who is "mischievous" is said to be "bösartig", "spitzbübisch", "boshaft" or "schadenfroh" in German.
im laughing at you
Because laughing at someone is considered unethical one needs to be disciplined.
Schadenfreude.
Mit jemand ausgehen=I am dating someone.
The Luhya translation of the English word 'Laughing' is "Okhutsekha".