deer (n.)
Old English deor "wild animal, beast, any wild quadruped," in early Middle English also used of ants and fish, from Proto-Germanic *deuzam, the general Germanic word for "animal" (as opposed to man), but often restricted to "wild animal" (source also of Old Frisian diar, Dutch dier, Old Norse dyr, Old High German tior, German Tier "animal," Gothic dius "wild animal," also see reindeer).

This is perhaps from PIE *dheusom "creature that breathes," from root *dheu- (1) "cloud, breath" (source also of Lithuanian dusti "gasp," dvėsti "gasp, perish;" Old Church Slavonic dychati "breathe"). For possible prehistoric sense development, compare Latin animal from anima "breath").

The sense specialization to a specific animal began in Old English (the usual Old English word for what we now call a deer was heorot; see hart), was common by 15c., and is now complete. It happened probably via hunting, deer being the favorite animal of the chase (compare Sanskrit mrga- "wild animal," used especially for "deer").

Source: https://www.etymonline.com/word/deer

bigot (n.)
1590s, "sanctimonious person, religious hypocrite," from French bigot (12c.), which is of unknown origin. Sense extended 1680s to other than religious opinions.

Earliest French use of the word is as the name of a people apparently in southern Gaul, which led to the theory, now considered doubtful on phonetic grounds, that the word comes from Visigothus. The typical use in Old French seems to have been as a derogatory nickname for Normans, leading to another theory (not universally accepted) that traces it to the Normans' (alleged) frequent use of the Germanic oath bi God. OED dismisses in a three-exclamation-mark fury one fanciful version of the "by god" theory as "absurdly incongruous with facts." At the end, not much is left standing except Spanish bigote "mustache," which also has been proposed as the origin of the word, but not explained, so the chief virtue of that theory is the lack of evidence for or against it.

In support of the "by God" theory the surnames Bigott, Bygott are attested in Normandy and in England from the 11c., and French name-etymology sources (such as Dauzat) explain it as a derogatory name applied by the French to the Normans and representing "by god." The English were known as goddamns 200 years later in Joan of Arc's France, and during World War I Americans serving in France were said to be known as les sommobiches (see son of a bitch) for their characteristic oaths. But the sense development in bigot would be difficult to explain. According to Donkin, the modern use first appears in French in 16c. This and the earliest English sense, "religious hypocrite," especially a female one, might have been influenced by or confused with beguine (q.v.) and the words that cluster around it.

Source: https://www.etymonline.com/word/bigot

warlock (n.)
Old English wærloga "traitor, liar, enemy, devil," from wær "faith, fidelity; a compact, agreement, covenant," from Proto-Germanic *wera- (source also of Old High German wara "truth," Old Norse varar "solemn promise, vow", High German wahr, "true"), from PIE root *were-o- "true, trustworthy" (whence Latin verus, "true"). Second element is an agent noun related to leogan "to lie" (see lie (v.1); compare Old English wordloga "deceiver, liar").

Original primary sense seems to have been "oath-breaker;" given special application to the devil (c. 1000), but also used of giants and cannibals. Meaning "one in league with the devil" is recorded from c. 1300. Ending in -ck (1680s) and meaning "male equivalent of a witch" (1560s) are from Scottish. Related: Warlockery.

Source: https://www.etymonline.com/word/warlock

nightmare (n.)
c. 1300, "an evil female spirit afflicting men (or horses) in their sleep with a feeling of suffocation," compounded from night + mare (n.3) "goblin that causes nightmares, incubus." The meaning shifted mid-16c. from the incubus to the suffocating sensation it causes. Sense of "any bad dream" is recorded by 1829; that of "very distressing experience" is from 1831. Cognate with Middle Dutch nachtmare, German Nachtmahr. An Old English word for it was niht-genga.

mare (n.3)
"night-goblin, incubus, oppressed sleep," Old English mare "incubus, nightmare, monster," from mera, mære, from Proto-Germanic *maron "goblin" (source also of Middle Low German mar, Middle Dutch mare, Old High German mara, German Mahr "incubus," Old Norse mara "nightmare, incubus"). This is from PIE *mora- "incubus" (source also of first element in Old Irish Morrigain "demoness of the corpses," literally "queen of the nightmare," also Bulgarian, Serbian mora, Czech mura, Polish zmora "incubus"). Also compare French cauchemar "nightmare," with first element from Old French caucher "to trample" and second element from Germanic.

thread (n.) ¹
Old English þræd "fine cord, especially when twisted" (related to þrawan "to twist"), from Proto-Germanic *thredu- "twisted yarn" (source also of Old Saxon thrad, Old Frisian thred, Middle Dutch draet, Dutch draad, Old High German drat, German Draht, Old Norse þraðr), literally "twisted," from suffixed form of PIE root *tere- (1) "to rub, turn." Meaning "spiral ridge of a screw" is from 1670s. Threads, slang for "clothes" is 1926, American English.

threaded (a.) ²

1. Having threads.
2. Arranged in a thread.

threading (n.) ³

The act or process by which something is threaded (in various senses).

thread necromancy (n.) ⁴

On an Internet forum, the act of posting in a thread that is already considered dead or/and out of discussion.

masturbation (n.)
"deliberate erotic self-stimulation," 1711 (earlier as mastupration, 1620s), from French masturbation and directly from Modern Latin masturbationem (nominative masturbatio), noun of action from past-participle stem of Latin masturbari "to masturbate."

The long-standing speculation is that this Latin word is altered (probably by influence of turbare "to disturb, confuse") from *manstuprare, from manu, ablative of manus "hand" (see manual) + stuprare "defile" (oneself), from stuprum "defilement, dishonor," related to stupere "to be stunned, stupefied" (see stupid). Hence the earliest form of the word in English. But perhaps the first element represents an unattested *mazdo- "penis" [OED]. An earlier technical word for this was onanism. Related: Masturbational.

Farmer and Henley ["Slang and Its Analogues," 1898] lists among the slang terms for "to masturbate" or "masturbation" frig (which they trace to Latin fricare "to rub") to bob; to box the Jesuit; to chuff, to chuffer; to claw; to digitate (of women); to fight one's turkey (Texan); to handle; to indorse; to milk; to mount a corporal and four; to dash one's doodle; and they note that it was "sometimes known as KEEPING DOWN THE CENSUS."