Derived from the verb nest (“to carry”) with vowel change, like nasta (“burden”), also from nest; the k follows the model of laisks (“indolent, lazy”), from laist (“to allow”). For the semantic change, consider terms like the (colloquial) derived verb nesties (“to run quickly”) (< “to carry oneself”). Cognates include Lithuanian našiai̇̃ (“swiftly, nimbly”).