The other day, Dad was roped in to play 'tag' with Chastan and Cheryl. While playing, something made Chastan angry. He just stopped in his tracks, stood there with an angry face and went "STUPID STUPID STUPID ".
Dad did not say anything then because, first he was stunned and second, most importantly, he did not want put any emphasis that this was not an appropriate word to be used in anger.
Again on another occcassion in the car, he used this word. Then last week at the bookstore at Jusco, someone accidently knocked into him. Annoyed, Chastan got up and said "Stupid" but luckily he was not loud and Dad was grateful, the chap who bumbed into Chastan could not have heard it.
Without reprimanding him, Dad said to Chastan "You should not use that word" and then continued "Where did you learn that word?"
"TV" shouted Cheryl who was nearby.
Then another time when Mummy scolded him, Chastan went "Stupid, Mummy stupid"