From *zatъxnǫti + *-lъ. *<span class="searchmatch">zatъxlъ</span> musty East <span class="searchmatch">Slavic</span>: Old East <span class="searchmatch">Slavic</span>: затъхлъ (zatŭxlŭ) Old Ruthenian: *затхлый (*zatxlyj) Belarusian: затхлы (zatxly)...
Reconstruction:Proto-Slavic/<span class="searchmatch">zatъxlъ</span> Sławski, Franciszek, editor (1974), “-lъ”, in Słownik prasłowiański [<span class="searchmatch">Proto</span>-<span class="searchmatch">Slavic</span> Dictionary] (in Polish), volume...