Saturday-night special

Etymology
Attested from 1917, akin to Satuday-night pistol attested from 1915. Not entirely clear, but perhaps from phrases like “Saturday night pistol slaying” and “Saturday night pistol scrape” often found in early 20th-c. local crime reporting due to the fact that Saturday evening has been the peak time for homicides and similar crimes. Also likely to be enforced by the obsolete meaning of a cheap sale and usage of "Special" in the context of more powerful firearms like Colt Police Positive Special.

Noun

 * 1)  An inexpensive, easily obtained handgun.
 * 2)  An overnight weekend train.
 * 3)  A seasonal (usually October to December) sale on Saturday evening.
 * 4)  A girl who can be dated easily on Saturday evenings.
 * 5)  An unexpected takeover bid that gives its opponents little time to respond.
 * 1)  An unexpected takeover bid that gives its opponents little time to respond.