adj.1. Breathing with difficulty; gasping: was breathless from running.
2. a. Excited or tense, often to the point of holding the breath: a breathless audience.
b. Tense or exciting, often in causing or being characterized by holding of the breath: breathless anticipation.
3. a. Not breathing; without breath.
b. Dead.
4. Having no air or breeze; still: a breathless summer day.