1.Definition: appearing dead; not breathing or having no perceptible pulse

Related Adjective(s):inanimate, pulseless

2.Definition: 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"

Related Adjective(s):dyspneal, dyspneic, dyspnoeal, dyspnoeic

3.Definition: tending to cause suspension of regular breathing

"A breathless flight"

Related Adjective(s):breathtaking