Adjective breathless has 3 senses
  1. breathless, dyspneic, dyspnoeic, dyspneal, dyspnoeal - not breathing or able to breathe except with difficulty; "breathless at thought of what I had done"; "breathless from running"; "followed the match with breathless interest"
    Antonyms: breathing, eupneic, eupnoeic, breathed, exhaling, huffing, puffing, puffy, inhaling, snoring, snorting
  2. breathless, breathtaking - tending to cause suspension of regular breathing; "a breathless flight"; "breathtaking adventure"
    Antonym: unexciting (indirect, via exciting)
  3. breathless, inanimate, pulseless - appearing dead; not breathing or having no perceptible pulse; "an inanimate body"; "pulseless and dead"
    Antonym: alive (indirect, via dead)