Quocunque aspicio, nihil est nisi mortis imago—Wherever I look I see nothing but some form of death. Ovid.
Quod avertat Deus!—God forbid!
Quod cito fit, cito perit—What is done quickly does not last long.
Quod commune cum alio est, desinit esse proprium—What we share with another ceases to be our own. Quinct.
Quod decet honestum est et quod honestum est decet—What is becoming is honourable, and what is honourable is becoming. Cic.
Quod eorum minimis mihi—As to the least of 5 these, so to me. M.
Quod erat demonstrandum—Which was to be proved.
Quod erat faciendum—Which was to be done.
Quod est absurdum—Which is absurd.
Quod est ante pedes nemo spectat: cœli / Scrutantur plagas—What is at his feet no one looks at; they scan the tracks of heaven. Enn.