Refers to where someone gradually "progresses down the slippery slope" into more and more unlawful (i.e., "criminal") behavior.
A lot of the more-serious legal-offenders started out with just petty-small stuff like throwing eggs or snitching a roll of Life-Savers at a drug store, but then they incrimintally progressed downhill from there until they were doing "heavier" stuff like joy-riding or smashing mailboxes.
by QuacksO July 24, 2018