Jump on is an expression used to describe a situation in which someone acts quickly and aggressively. The crossword solutions for this term are REPRIMAND (9 letters), ATTACK (6 letters), SEIZE (5 letters), BERATE (6 letters), and POUNCE (6 letters). REPRIMAND is an act of scolding or expressing disapproval, while ATTACK is an act of aggression or hostility. SEIZE is to take hold of something suddenly and forcibly, while BERATE is to criticize harshly. Finally, POUNCE is to move quickly and forcefully, usually with the intention of attacking.