"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."
Lucky break is attested from 1884 in billiards; 1872 as "failure or break-down which turns out to be fortunate." Lucky accident is from 1660s. Lucky dog "unusually lucky person" is from 1842. Lucky Strike as the name of a U.S. brand of cigarettes (originally chewing tobacco) popular in the World War II years is said to date from 1871. Its popularity grew from 1935 when the brand's maker picked up sponsorship of radio's "Your Hit Parade."
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.