When u dont want to use the 'r' word because apparently its not politically correct. Tards can also be categorised into groups or gangs of stupid people who can be very dumb.
Unlike the word "retard" or as others call it "The R-Slur", Tard can be a term used to call out someone for making a minor mistake not to be used as calling them out for being "autistic" because they aren't, they just made a little dumb mistake.
"Why the f*ck didn't you take out the trash before mom got home from work like she asked you to, you f*cking Tard."
"You for real showed up to work 2 minutes late, You f*cking Tard."