The mayor sat back heavily, the plush cushion behind him sighing deeply.
They listened with audible outrage, sighing and groaning in disbelief.
mid-13c., probably a Middle English back-formation from sighte, past tense of Old English sican "to sigh," perhaps echoic of the sound of sighing. Related: Sighed; sighing.
early 14c., from sigh (v.).