1580s, "lacking, wanting, incomplete;" c. 1600 "not having a full or adequate supply," from Latin deficientem (nominative deficiens), present participle of deficere "to desert, revolt, fail," from de "down, away" (see de-) + combining form of facere "to do, make" (from PIE root *dhe- "to set, put"). Compare defective. Related: Deficiently.
late 14c., defeten, diffaiten, "overcome (with sorrow or anger)," from Anglo-French defeter, from Old French desfait, past participle of desfaire "to undo," from Vulgar Latin *diffacere "undo, destroy," from Latin dis- "un-, not" (see dis-) + facere "to do, perform," from PIE root *dhe- "to set, put."
From early 15c. as "bring ruination, cause destruction" (now obsolete in this sense); from late 15c. as "frustrate, prevent the success of." Sense of "deprive of something expected, desired or striven for" is from 1530s. Meaning "overcome in a contest of any kind" is from 1560s. Related: Defeated; defeating. Compare defect, deficient.
*dhē-, Proto-Indo-European root meaning "to set, put."
It forms all or part of: abdomen; abscond; affair; affect (v.1) "make a mental impression on;" affect (v.2) "make a pretense of;" affection; amplify; anathema; antithesis; apothecary; artifact; artifice; beatific; benefice; beneficence; beneficial; benefit; bibliothec; bodega; boutique; certify; chafe; chauffeur; comfit; condiment; confection; confetti; counterfeit; deed; deem; deface; defeasance; defeat; defect; deficient; difficulty; dignify; discomfit; do (v.); doom; -dom; duma; edifice; edify; efface; effect; efficacious; efficient; epithet; facade; face; facet; facial; -facient; facile; facilitate; facsimile; fact; faction (n.1) "political party;" -faction; factitious; factitive; factor; factory; factotum; faculty; fashion; feasible; feat; feature; feckless; fetish; -fic; fordo; forfeit; -fy; gratify; hacienda; hypothecate; hypothesis; incondite; indeed; infect; justify; malefactor; malfeasance; manufacture; metathesis; misfeasance; modify; mollify; multifarious; notify; nullify; office; officinal; omnifarious; orifice; parenthesis; perfect; petrify; pluperfect; pontifex; prefect; prima facie; proficient; profit; prosthesis; prothesis; purdah; putrefy; qualify; rarefy; recondite; rectify; refectory; sacrifice; salmagundi; samadhi; satisfy; sconce; suffice; sufficient; surface; surfeit; synthesis; tay; ticking (n.); theco-; thematic; theme; thesis; verify.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit dadhati "puts, places;" Avestan dadaiti "he puts;" Old Persian ada "he made;" Hittite dai- "to place;" Greek tithenai "to put, set, place;" Latin facere "to make, do; perform; bring about;" Lithuanian dėti "to put;" Polish dziać się "to be happening;" Russian delat' "to do;" Old High German tuon, German tun, Old English don "to do."
1630s, "state of falling short, a lack or failing;" 1660s, "that in which a person or thing is deficient, inadequacy," from Late Latin deficientia, from deficient-, present-participle stem of deficere "to desert, revolt, fail," from de "down, away" (see de-) + combining form of facere "to do, make" (from PIE root *dhe- "to set, put"). The older English word, now rare or obsolete, was deficience (mid-15c.).