Definition of "drop off"

drop off

verb
third-person singular simple present drops off, present participle dropping off, simple past and past participle dropped off
1. (idiomatic, intransitive) To fall asleep.
  Quotations
  And when the Boy dropped off to sleep, the Rabbit would snuggle down close under his little warm chin and dream, with the Boy's hands clasped close round him all night long.
  1921 June, Margery Williams, “The Velveteen Rabbit: Or How Toys Become Real”, in Harper’s Bazar, volume LVI, number 6 (2504 overall), New York, N.Y.: International Magazine Company
2. (idiomatic, transitive, especially US) To deliver; to deposit or leave; to allow passengers to alight.
  Quotations
  After dropping off travellers at Foregate Street, my train terminates at Shrub Hill - a station which boasts one of the best selection [sic] of semaphore signals left in the country.
  2020 December 2, Paul Bigland, “My weirdest and wackiest Rover yet”, in Rail, page 67
3. To fall.
4. To lessen or reduce.