1Drowsiness; the strong sleepy feeling that suddenly overcomes someone.
午後の授業中、睡魔に襲われて居眠りしてしまった。
During the afternoon class I was overcome by drowsiness and dozed off.
長時間の運転で睡魔が来たら、無理せず休憩を取ってください。
If drowsiness hits you during long drives, don't push it—take a break.
会議が退屈だと睡魔に負けそうになることがある。
If a meeting is boring, you might almost be defeated by drowsiness.
2The sandman; a personified figure who brings sleep (used figuratively or in literature).
絵本の中では睡魔が子どもに砂をかけて眠らせる場面が描かれている。
In picture books, the sandman is depicted sprinkling sand on children to make them sleep.
疲れていると、まるで睡魔が背中を押すように眠くなる。
When I'm tired, I feel sleep coming as if the sandman were pushing me from behind.