Etymology
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carelessness (n.)
Old English carleasnes "freedom from anxiety;" see careless + -ness. Original sense obsolete. Modern meaning "heedlessness, negligence" (1560s) probably is a fresh formation.
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recklessness (n.)

"state or quality of being heedless," Middle English rechelesnes, from Old English recceleasnes "recklessness, carelessness, negligence;" see reckless + -ness.

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inadvertence (n.)

"carelessness, negligence, inattention," mid-15c., from Old French inadvertance "thoughtlessness, heedlessness" (14c.), from Scholastic Latin inadvertentia, from in- "not" (see in- (1)) + advertentia, from Latin advertere "to direct one's attention to," literally "to turn toward" (see advertise).

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insouciance (n.)
1820, from French insouciance "heedless indifference or unconcern," from insouciant "carelessness, thoughtlessness, heedlessness," from in- "not" (see in- (1)) + souciant "caring," present participle of soucier "to care," from Latin sollicitare "to agitate" (see solicit).
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cut-and-paste (adj.)

"made or composed by piecing together existing parts," by 1938 with reference to trick photographs; see cut (v.) + paste (v.). By 1959 with reference to doing things with haste, carelessness, or lack of inspiration.

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negligence (n.)

"heedless disregard of duty, inactivity, indifference, habit of omitting to do things which ought to be done," mid-14c., necligence, from Old French negligence "negligence, sloth; injury, injustice" (12c.), and directly from Latin neclegentia, neglegentia "carelessness, heedlessness, neglect," from neglegentem (nominative neglegens) "heedless, careless, unconcerned," present participle of neglegere "to neglect" (see neglect (v.)).

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malpractice (n.)

1670s, "bad treatment of disease, pregnancy, or bodily injury from ignorance, carelessness, or with criminal intent," a hybrid coined from mal- + practice (n.). Also used for "illegal action by which a person seeks a benefit for himself while in a position of trust" (1758).

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mendacious (adj.)

"given to lying, speaking falsely; having the characteristics of a lie, false, untrue," 1610s, from French mendacieux and directly from Latin mendacium "a lie, untruth, falsehood, fiction," from mendax (genitive mendacis) "lying, deceitful," from menda "fault, defect, carelessness in writing," from PIE root *mend- "physical defect, fault" (see amend (v.)). The sense evolution of Latin mendax was influenced by mentiri "to speak falsely, lie, deceive." Related: Mendaciously; mendaciousness.

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slip (v.)
early 14c., "to escape, to move softly and quickly," from an unrecorded Old English word or cognate Middle Low German slippen "to glide, slide," from Proto-Germanic *slipan (source also of Old High German slifan, Middle Dutch slippen, German schleifen "to glide, slide"), from PIE *sleib-, from root *(s)lei- "slimy, sticky, slippery" (see slime (n.)).

From mid-14c. with senses "lose one's footing," "slide out of place," "fall into error or fault." Sense of "pass unguarded or untaken" is from mid-15c. That of "slide, glide" is from 1520s. Transitive sense from 1510s; meaning "insert surreptitiously" is from 1680s. Related: Slipped; slipping. To slip up "make a mistake" is from 1855; to slip through the net "evade detection" is from 1902. To let (something) slip originally (1520s) was a reference to hounds on a leash; figurative use "allow to escape through carelessness" is from 1540s.
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