Let Slide Meaning

(idiomatic) To allow the condition of something to deteriorate due to negligence or apathy.

Example:   The police officer let the ticket slide when she found her brother-in-law's car illegally parked.
  The administrator let the minor infraction slide with only a disapproving look.
14th century Geoffrey Chaucer, The Canterbury Tales
  But nathelees she moste a tyme abyde,
  And with good hope lete her sorrow slyde.
  The judge let me slide on the speeding, but not on a $200 seat-belt violation.
  He let the farm slide after inheriting it from his father.
Used other than as an idiom: see let,‎ slide.