Etymology
Advertisement
duty (n.)

late 14c., duete, "obligatory service, that which ought to be done," also "the force of that which is morally right," from Anglo-French duete, from Old French deu "due, owed," hence "proper, just" (on the notion of "that which one is bound by natural, moral, or legal obligation to do or perform"); from Vulgar Latin *debutus, from Latin debitus, past participle of debere "to owe," originally, "keep something away from someone," from de- "away" (see de-) + habere "to have" (from PIE root *ghabh- "to give or receive"). Related: Duties.

Military sense of "a requisite service" is by 1580s. The sense of "tax or fee on imports, exports, etc." is from late 14c.; hence duty-free (adv.) "free from tax or duty" (1680s), and, as a noun, "duty-free article" (1958), "duty-free shop" (by 1980).

Related entries & more 
Advertisement
heavy-duty (adj.)
"durable, strong," 1903; see heavy (adj.) + duty.
Related entries & more 
off-duty (adj.)

"not employed or occupied with one's normal work," 1743, from off (prep.) + duty.

Related entries & more 
dutiable (adj.)

"subject to a customs duty," 1774, from duty + -able.

Related entries & more 
dutiful (adj.)

"performing the duties required by social or legal obligation; obediently respectful," 1550s, from duty + -ful. Related: Dutifully; dutifulness. Shakespeare uses duteous.

Related entries & more 
Advertisement
*ghabh- 
also *ghebh-, Proto-Indo-European root meaning "to give or receive." The basic sense of the root probably is "to hold," which can be either in offering or in taking.

It forms all or part of: able; avoirdupois; binnacle; cohabit; cohabitation; debenture; debit; debt; dishabille; due; duty; endeavor; exhibit; exhibition; forgive; gavel; gift; give; habeas corpus; habiliment; habit; habitable; habitant; habitat; habitation; habitual; habituate; habituation; habitude; habitue; inhabit; inhibit; inhibition; malady; prebend; prohibit; prohibition; provender.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit gabhasti- "hand, forearm;" Latin habere "to have, hold, possess," habitus "condition, demeanor, appearance, dress;" Old Irish gaibim "I take, hold, I have," gabal "act of taking;" Lithuanian gabana "armful," gabenti "to remove;" Gothic gabei "riches;" Old English giefan, Old Norse gefa "to give."
Related entries & more 
ex officio 
Latin, "in discharge of one's duties," literally "out of duty," from ex "out of" (see ex-) + officio, ablative of officium "duty" (see office).
Related entries & more 
inofficious (adj.)
c. 1600, "neglecting one's duty;" in law, "not in accord with one's moral duty," 1660s, from Medieval Latin inofficiosus "contrary to duty; harmful," from in- "not, opposite of" (see in- (1) + Latin officiosus "dutiful, obliging" (see officious).
Related entries & more 
defaulter (n.)

"one who fails to perform some duty or obligation," 1650s, agent noun from default (v.).

Related entries & more 
endeavor (n.)
early 15c., "pains taken to attain an object," literally "in duty," from phrase put (oneself) in dever "make it one's duty" (a partial translation of Old French mettre en deveir "put in duty"), from Old French dever "duty," from Latin debere "to owe," originally, "keep something away from someone," from de- "away" (see de-) + habere "to have" (from PIE root *ghabh- "to give or receive"). One's endeavors meaning one's "utmost effort" is from late 15c.
Related entries & more