Lament
Noun and する verb
たんそく
他人よりも自分がずっと短足だと気づいた時、彼は深々と嘆息して、日本短足協会へと向かった。
When he realized that his legs were much shorter than other peoples’ he sighed deeply and headed to the Japan Short Leg Association.
A sigh breath is a sigh.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.