Thirty years ago when I graduated from high school, I got a lot of well-wishing cards from family and friends. All of them conveyed the same wish, to congratulate me on my graduation. Most of the cards said “Congratulations Graduate” on the front. One of them had a cute kitten wearing a cap and gown, and the caption, “conGRADulations”. I thought it was pretty cute, how the “card people” had combined the words “congratulations” and “graduate”. Obviously a lot of other people thought it was cute too, and the card sold well. Now, you almost can’t find a graduation card that spells “congratulations” properly. I even see people writing the misspelled version as they “congradulate” their friends who are getting engaged, married, having a significant anniversary, and giving birth.
“Congratulations” is a word that conveys the intent to pass well-wishes on as a person celebrates an achievement. “Congradulations” is a hybrid word made up by a greeting card company. It is barely appropriate as a bad pun for people graduation from high school or college. It is never appropriate on any other occasion. Please, congratulate responsibly!