Where does “άκαρπος” come from?

άκαρπος (Greek) comes from Ancient Greek ἄκαρπος, from Ancient Greek ἀ-, from Proto-Hellenic hə-, from Proto-Indo-European sm̥-, from Proto-Indo-European sem- — together, one.

άκαρπος (Greek): barren, unfruitful, fruitless, infertile;...