"stupid person, eccentric person," 1920s slang, perhaps a back-formation from dippy. "Dipshit is an emphatic form of dip (2); dipstick may be a euphemism or may reflect putative dipstick 'penis' " [DAS].
Old English dyppan "to plunge or immerse temporarily in water, to baptize by immersion," from Proto-Germanic *daupejanan (source also of Old Norse deypa "to dip," Danish døbe "to baptize," Old Frisian depa, Dutch dopen, German taufen, Gothic daupjan "to baptize"), related to Old English diepan "immerse, dip," and probably a causative of Proto-Germanic *deup- "deep" (see deep (adj.)).
Intransitive sense of "plunge into water or other liquid" and transferred sense "to sink or drop down a short way" are from late 14c. From c. 1600 as "to raise or take up by a dipping action;" from 1660s as "to incline downward;" from 1776 as "to lower and raise (a flag, etc.) as if by immersing."
ruminant mammal, Old English sceap, scep, from West Germanic *skæpan (source also of Old Saxon scap, Old Frisian skep, Middle Low German schap, Middle Dutch scaep, Dutch schaap, Old High German scaf, German Schaf), of unknown origin. Not found in Scandinavian (Danish has faar for "sheep") or Gothic (which uses lamb), and with no known cognates outside Germanic. The more usual Indo-European word for the animal is represented in English by ewe.
The plural form was leveled with the singular in Old English, but Old Northumbrian had a plural scipo. Used since Old English as a type of timidity and figuratively of those under the guidance of God. The meaning "stupid, timid person" is attested from 1540s. The image of the wolf in sheep's clothing was in Old English (from Matthew vii.15); that of separating the sheep from the goats is from Matthew xxv.33. To count sheep in a bid to induce sleep is recorded from 1854 but seems not to have been commonly written about until 1870s. It might simply be a type of a tedious activity, but an account of shepherd life from Australia from 1849 ["Sidney's Emigrant's Journal"] describes the night-shepherd ("hut-keeper") taking a count of the sheep regularly at the end of his shift to protect against being answerable for any animals later lost or killed.
Sheep's eyes "loving looks" is attested from 1520s (compare West Frisian skiepseach, Dutch schaapsoog, German Schafsauge). A sheep-biter was "a dog that worries sheep" (1540s); "a mutton-monger" (1590s); and "a whore-monger" (1610s, i.e. one who "chases mutton"); hence Shakespeare's sheep-biting "thieving, sneaky."
1590s, "act of dipping," from dip (v.). Sense of "a downward slope" is by 1708. Meaning "liquid into which something is to be dipped" is attested by 1825, in 19c. especially "sweet sauce for pudding, etc.," also "juices and fat left after cooking meat." The sense "thick, savory sauce for dunking pieces of raw vegetables" (by 1962) is probably a modern re-coinage.
"pertaining to or of the nature of sheep," 1824, from Late Latin ovīnus, from Latin ovis "sheep," from PIE root *owi- "sheep" (see ewe).