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.
early 14c., "minor ecclesiastical court officer" (mid-13c. as a surname), from Old French oficial "law officer; bishop's representative" (12c.) and directly from Late Latin officialis "attendant to a magistrate, public official," noun use of officialis (adj.) "of or belonging to duty, service, or office" (see official (adj.)). From mid-14c. as "a domestic retainer in a household;" the meaning "person in charge of some public work or duty, one holding a civil appointment" is recorded from 1550s.
c. 1300, obligacioun, "a binding pledge, commitment to fulfill a promise or meet conditions of a bargain," from Old French obligacion "obligation, duty, responsibility" (early 13c.) and directly from Latin obligationem (nominative obligatio) "an engaging or pledging," literally "a binding" (but rarely used in this sense), noun of action from past-participle stem of obligare "to bind, bind up, bandage," figuratively "put under obligation" (see oblige). The notion is of binding with promises or by law or duty.
The meaning "that which one is bound or obliged to do, especially by moral or legal claims a duty" is from c. 1600. That of "state or fact of being bound or constrained by gratitude to requite benefits, moral indebtedness," also is from c. 1600. Related: Obligational.
