means A short, soft burst of air, breath, smoke, or steam — or, by extension, something light and inflated, whether a pastry, a bit of swollen praise, or a small expulsion of effort.

from From Old English 'pyff,' an imitative word — its very sound mimics the breath it names, the lips pursing to push out air. This makes it onomatopoeic, born from the act it describes, with cousins across the Germanic languages doing the same trick (German 'puffen,' to blow or pop). The sense of 'inflated, exaggerated praise' grew naturally: just as a puff of air swells a thing up, so flattery puffs up reputation and pride.