Congratulations!
Joyful times go hand in hand with congratulations. When addressing graduates, newlyweds, or anyone with good news, a hearty “Congratulations!” or a swift “Congrats!” is in order. Congratulants, “people who congratulate,” have been using the pluralized expression congratulations, which stems from the Latin gratus meaning “pleasing,” since the 1600s.
The singular noun meaning “the act of congratulating” has been around since the late 1500s.