Definition of jump off in English:

jump off

phrasal verb

  • (of a military campaign) begin.

    ‘the air-attack phase will continue before the ground attack jumps off’
    • ‘The attack jumped off at Honnef, 10 April.’
    • ‘On the morning of 13 May, the 6th Marine Division attack was scheduled to jump off at 0730.’
    • ‘The attack jumped off six hours later.’
    • ‘The final assault jumped off at 1515 from a crossroads 500 yards south of Clochimont.’
    • ‘The mines were cleared without casualty, and the Marine assault jumped off at 1000.’
    • ‘The First Infantry Division attack jumped off at 0600.’