Standard word for an alarm clock; used in everyday contexts.
目覚まし時計をセットしてから寝た。
I set the alarm clock before going to bed.
今朝は目覚まし時計が鳴らなかった。
The alarm clock didn't go off this morning.
Since I have an early start tomorrow, I set the alarm clock for 6.
I couldn't wake up even when the alarm clock went off.
Still half-asleep, I turned off the alarm clock without meaning to.