STAND FOR?
In UFO, possibly an alien craft.
Unidentified
Captain Ahab's whaling vessel (6)
The Pequod
Technically, the measure of the body's inertia is known as this property of matter.
Mass
This word for "nothing" precedes "and void" to mean "not valid."
Null
Skyy and Smirnoff.
Vodka
In SCUBA.
Underwater
The most worldly of the Three Musketeers (7)
Porthos
In palynology, scientists study the past distribution of seed plants by looking at grains of this.
Pollen
Something that is in vain is "all for" this, from the Old English for "nothing."
Naught
Bacardi and Myers's.
Rum
In the government department HUD.
Urban
Ophelia's pop (8)
Polonius
The scapula was once called the blade bone as well as this blade.
Shoulder blade
In "Casablanca" Rick says, "It doesn't take much to see that the problems of three little people don't amount to" this.
A hill of beans.
Glenlivet and Chivas Regal.
Scotch
In the ACLU.
Union
Russian writer who came to shove, 1799-1837 (7)
Pushkin
In 1674 this Dutchman, using microscopes that he made, became the first to describe red blood cells.
Van Leeuwenhoek
This man's "choice" is the absence of a real alternative - you take that which is offered or nothing.
Hobson's choice.
Gekkeikan and Ozeki.
Sake
In the committee known as HUAC.
Un-American
Ancient Greek poet who "ode" a lot (6)
Pindar
The proton consists of two types of this elementary particle: 2 up and 1 down.
Quarks
In math, a solution to an equation in which the value of every variable is equal to zero is called this, like certain "pursuits."
Trivial
Hendrick's and Boodles.
Gin