"an inexpressible something," French, literally "I do not know what."
[T]hey are troubled with the je-ne-scay-quoy, that faign themselves sick out of niceness but know not where their own grief lies, or what ayls them. [Thomas Blount, "Glossographia," 1656]
Though both historic and historical have been used in both senses by respected authors, now the tendency is to reserve historic for what is noted or celebrated in history; historical for what deals with history. The earliest adjective form of the word in English was historial (late 14c., from Late Latin historialis), which meant "belonging to history; dealing with history; literal, factual, authentic," and also "of historical importance" (early 15c.).
1540s, "fixed, permanent," adjectival use of stayed, past participle of stay (v.). Meaning "sober, sedate" first recorded 1550s. As in Philip Sidney's justice staid, explained by Ruskin as "The desire of what is just, being stayed or restrained within the limits of what can be accomplished by just means." Related: Staidly.
1871, a word invented by Lewis Carroll ("Jabberwocky"). Anyone's guess what he meant by it.
1610s, "a pun, a play on words," probably a diminutive of obsolete quib "evasion of a point at issue" (1540s), which is based on Latin quibus? "by what (things)?" Its extensive use in legal writing supposedly gave it the association with trivial argument: "a word of frequent occurrence in legal documents ... hence associated with the 'quirks and quillets' of the law." [OED].
Latin quibus is dative or ablative plural of quid "in what respect? to what extent?; how? why?," neuter of relative pronoun quis (from PIE root *kwo-, stem of relative and interrogative pronouns).