"failure or omission of duty or obligation," 1630s, from Late Latin delinquentia "fault, crime, delinquency," from Latin delinquentem (see delinquent).
"seduced or corrupted from duty or virtue, vitiated in morals or purity of character," 1590s, past-participle adjective from debauch (v.). Related: Debauchedness.
German tasche "pocket" is from the same Vulgar Latin source (via Old High German tasca), with presumable sense evolution from "amount of work imposed by some authority," to "payment for that work," to "wages," to "pocket into which money is put," to "any pocket."
late 15c., "one who fails to perform a duty or discharge an obligation," also, generally, "an offender against the law," a noun use from Latin delinquentum (nominative delinquens), present participle of delinquere "to fail; be wanting, fall short; do wrong, transgress, offend," from de- "completely" (see de-) + linquere "to leave" (from PIE root *leikw- "to leave"). As an adjective, "failing or neglectful in duty," from c. 1600 in English.
late 14c., "performing a service" (a sense now obsolete); c. 1400, "required by duty," from Old French oficial "official; main, principal" (14c., Modern French officiel) and directly from Late Latin officialis "of or belonging to duty, service, or office," from Latin officium "service, kindness, favor; official duty, function, business; ceremonial observance," literally "work-doing," from ops (genitive opis) "power, might, abundance, means" (related to opus "work," from PIE root *op- "to work, produce in abundance") + combining form of facere "to make, to do" (from PIE root *dhe- "to set, put").
Meaning "pertaining to an office or official position" is from c. 1600. That of "derived from the proper office or officer," hence "authorized," is by 1854.
1590s, "abandonment, state of being forsaken or abandoned" (formerly with a wider range than in modern use, such as of the sea withdrawing from the land), from Latin derelictionem (nominative derelictio) "an abandoning; a disregarding, neglecting," noun of action from past-participle stem of derelinquere (see derelict).
Sense of "act of leaving with an intention not to reclaim or reuse" is from 1610s. Meaning "failure, unfaithfulness, neglect" (with regard to duty, etc.) is by 1778. Phrase dereliction of duty attested from 1776.