That is, with abundant destruction. Concerning these prayers of the prophet against his enemies, See Poole on "Jeremiah 11:20".
Related Commentaries of Jeremiah 17:18
Jeremiah 17:18
18 Let them be confounded that persecute me, but let not me be confounded: let them be dismayed, but let not me be dismayed: bring upon them the day of evil, and destroye them with double destruction.