Hold Back Meaning

(idiomatic) to delay, especially in school

Example:   Don't hold back. Hit it as hard as you can.
  The dam can't hold back that much water.
2011 January 8, Chris Bevan, “Arsenal 1 - 1 Leeds”[1], BBC:
  Fabregas coolly slotted home after Ben Parker held back Theo Walcott and only a super Kasper Schmeichel save stopped Denilson winning it for the Gunners.
  He's a year older than his classmates because he was held back in second grade.