'wake-up call' definitions:
Definition of 'wake-up call'
(from WordNet)
noun
A warning to take action concerning something that was overlooked or neglected; "the bombing was a wake-up call to strengthen domestic security"
noun
A telephone call that you request be made a specific time in order to wake you up at that time (especially in hotels); "she left a wake-up call for 7 a.m."