Comments: PAT *pǝśǝ- 'to die', *ʕa-pǝśa- 'to get tired' (Abkh. ā́psa-ra, Abaz. ʕapsa-rá). PAK *pśǝ-. In Ub. - a compound whose second component (-χʷǝ-) is not quite clear.
The semantic developments 'to breathe' > 'get tired' and 'get tired' > 'die' are quite usual (cf. also the meanings of the corresponding root in EC).
