At-once Synonyms

Without delay or hesitation; with no time intervening
(Adverb)
Synonyms:
  1. at-a-time
  2. immediately
  3. instantly
  4. straightaway
  5. straight off
  6. directly
  7. now
  8. right away
  9. forthwith
  10. at-one-time
  11. like a shot