ju

jubilant (adj.) extremely joyful, happy (The crowd was jubilant when the firefighter carried the woman from the flaming building.)

judicious (adj.) having or exercising sound judgment (When the judicious king decided to compromise rather than send his army to its certain death, he was applauded.)

juxtaposition (n.) the act of placing two things next to each other for implicit comparison (The interior designer admired my juxtaposition of the yellow couch and green table.)