no obj.
1- be half asleep; doze intermittently昏昏欲睡, 假寐; 打瞌睡, 打盹：
he was beginning to drowse in his chair.
他坐在椅子里打起瞌睡来。
1.1
- with obj. archaic make sleepy〈古〉使昏昏欲睡.
1.2
- archaic be sluggish or inactive〈古〉呆滞, 不活跃：
let not your prudence drowse.
你要时刻保持谨慎。
词源
late 16th cent.: back-formation from DROWSY.