The Collaborative International Dictionary of English. 2000.
sighingly — adverb In a sighing way; with sighs … Wiktionary
sighingly — sigh·ing·ly … English syllables
sighingly — adverb Etymology: Middle English, from sihing, sighing (present participle of sihen, sighen to sigh) + ly : in a sighing manner : with sighing … Useful english dictionary