wake-up call

Noun wake-up call has 2 senses

• wake-up call(n = noun.communication) - a warning to take action concerning something that was overlooked or neglected; "the bombing was a wake-up call to strengthen domestic security"
is a kind of warning

• wake-up call(n = noun.communication) - 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."
is a kind of call, phone call, telephone call