What is the meaning of fall back?

verb

• Fall backwards and down.
• Hang (back) or fall (behind. in movement, progress, development, etc.)
  • synonyms: lag, dawdle, fall behind
• Move back and away from.
  • usage: "The enemy fell back"
• Retreat.
  • synonyms: lose, drop off, fall behind, recede
• Have recourse to.
  • usage: "The government resorted to rationing meat"
  • synonyms: resort, recur
• Go back to bad behavior.
  • usage: "Those who recidivate are often minor criminals"
  • synonyms: relapse, lapse, recidivate, regress, retrogress