breathless
adj.having trouble breathing because you are tired or excited. It can also describe a feeling of great wonder or surprise.
adj.characterised by difficulty in breathing, typically due to physical exertion, intense emotion, or shock. Often used to describe a state of suspense or awe.
“She was breathless after running up the stairs.”
“The hikers arrived at the summit breathless but happy to see the view.”
“The audience waited in breathless silence as the acrobat prepared for the final, most dangerous stunt of the evening.”
Commonly used both predicatively after linking verbs like 'be' or 'feel' and attributively before nouns.
“D ays and months pass in lonely, blunt-edged monotony, a low, breathless panic beating in my chest.”
From breath + -less.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.