qualm: Pang of guilt; pricking of conscience. Probably Old English “cwealm”=torment, pain, or injury.
quark: Elementary particle in sub-atomic physics. Coined 1939 by physicist Murray Gell-Mann from a nonsense word in “Finnegans Wake.”
quarrel:  To have an angry dispute; to argue. From Latin “querela” < “queri”=complain or lament + “-ela”=noun-forming suffix.
quarrel: Square-headed bolt or arrow especially for a crossbow. From Old French “quarel” < Latin “quadrus”=square.
quibble: Use ambiguous or irrelevant language or arguments to evade a point. A trivial objection. From Latin “quibus”=who or what.
quill: Hollow shaft of a feather, once used for writing. Middle English “quil” < Low German “quiele”=shaft of a feather.
quincunx: Pattern of five objects where four form a square and the fifth is in the middle. From Latin “quinque”=five + “uncia”=twelfth.
quiver: Case for holding or carrying arrows; 14th century slang for female genitals. From Old French “quivre”=case.
quiz: Set of questions provided as an entertainment or test. Obscure origin, possibly shortened “inquisitive” < Latin “inquirere”=to ask.
Quran: Holy book of Islam, variation of Koran. From Arabic “qur’an”=recitation < “qara’a”=to read.