From * molvis ‹ * mollvis ‹ * molduis , from Proto-Italic * moldus , from Proto-Indo-European * ml̥dus , from * (s)meld- , from Proto-Indo-European * (s)meld- ( “ to soften, melt ” ) . According to De Vaan, the term was likely remade from a u-stem to an i-stem. However, De Vaan suggests that the original u-stem is present in terms such as Latin molluscus , which he explains as a derivation from * moldusko- , from * mldu-sko- .
Cognates include Latin mola , blandus , mortārium , Old Prussian maldai ( “ boys ” ) , Welsh blydd ( “ soft ” ) , Old Church Slavonic младъ ( mladŭ , “ young ” ) , Sanskrit मृ॒दु ( mṛdú , “ soft; mild; weak ” ) , Old Armenian մեղկ ( mełk , “ soft; weak ” ) , Ancient Greek βλᾰδῠ́ς ( blădŭ́s , “ weak ” ) and ᾰ̓μᾰλδῡ́νω ( ămăldū́nō , “ to weaken; to destroy ” ) . More at mild .
An alternative hypothesis derives it from the Proto-Indo-European root * melh₂- ( “ to grind, crush, pulverize, mill ” ) via * mol-n-is ; more at malleus .