Collins COBUILD Advanced Learner's English Dictionary - drop off

1. see drop 9 2. If you drop off to sleep, you go to sleep. (INFORMAL) I must have dropped off to sleep... Just as I was dropping off, a strange thought crossed my mind. PHRASAL VERB: V P to sleep, V P 3. If the level of something drops off, it becomes less. Sales to the British forces are expected to drop off... = fall PHRASAL VERB: V P