Similar:

Opposite:

gasp of shock

, cry of despair

Types:

exhale

, release, relax, let go, ease up, unwind, unclench, breaout, more...

Phrases:

breathe a sigh of relief, breathed a sigh of relief, more...

Clues:

relieved sigh,   big sigh,   dreamy sigh,   happy exhale,   relaxed sigh,   smile of relief,   disappointed sigh,   stressed sigh,   relief sigh,   releif sigh