■ noun
1》 a long, deep, audible exhalation expressing sadness, tiredness, relief, etc.
2》 a sound resembling this.
■ verb
1》 emit a ~.
2》 ( ~ for ) literary yearn for.
Origin
ME (as v.): prob. a back-form. from ~te , past tense of siche , sike , from OE sīcan .