An alternate form of lawl or lol. When someone says 'hamar' it means that something is funny. Some may say it is the brown way of saying something is funny since 'hamar' sounds a bit like the name Kumar.
Person 1: "I ate too many nachos and puked!"
Person 2: "Hamar."
Person 1: "It's not funny."
Person 2: "HAMAR!"