Yours, Etc.: Origins and Uses of 8 Sign-Offs
1520s, from Latin neglectus, past participle of neglegere "to make light of, disregard, be indifferent to, not heed, not trouble oneself about," literally "not to pick up," variant of neclegere, from Old Latin nec "not" (see deny) + legere "pick up, select" (see lecture (n.)). Related: Neglected; neglecting.
1580s, from neglect (v.) or from Latin neglectus "a neglecting," noun use of past participle of neglegere.