火速

huǒsù
  1. at top speed
  2. at a tremendous lick

CEDICT

Entry Composition

1 火 huǒ
  1. fire
  2. urgent
  3. ammunition
  4. fiery or flaming
  5. internal heat (Chinese medicine)
  6. hot (popular)
  7. classifier for military units (old)
  8. Kangxi radical 86
2 速 sù
  1. fast
  2. rapid
  3. quick
  4. velocity