Definition of Clean hit

To win an inning that counters a good game your opponent just won.
The inning win that counters a good game your opponent just won.

Failure to hit an object ball at all with the cue ball. In most sets of rules, this is a foul like any other. However, in some variants of bar pool a table scratch while shooting for the 8 ball is a loss of game where other more minor fouls might not be, as is scratching on the 8 ball (neither result in a loss of game in most professional rules).
By way of drift from the above definition, the term is also applied by many league players to the foul in more standardized rules of failing to drive a (any) ball to a cushion, or to pocket a legal object ball, after the cue ball's initial contact with an object ball.
By way of entirely different derivation ("scratch off the table"), it can also mean knocking the cue ball (or more loosely, any ball) completely off the table.

Random method for pairing of opponents when setting up a bracket system for a tournament.

In snooker, the highest-value baulk colour, worth 4 points.

This is the act of looking over the stack, pile of balls in the middle of the table, to see if there are any opportunities in the game of one pocket.

Describing a situation where a pot is made more difficult, either by a pocket being partially blocked by another ball so that not all of it is available, or the cue ball path to the object ball's potting angle involves going past another ball very closely.

When playing 9 Ball, a dead ball is an object ball the falls into a pocket when a foul has been committed (for example, the shooter scratches or does not hit the lowest ball first). If keeping score by counting balls fallen, neither player gets the point for that ball.

To disguise the level of one's ability to play in various ways such as using a lemonade stroke; intentionally missing shots; making an uneven game appear "close"; purposefully losing early, inconsequential games. Sandbagging is a form of hustling, and in handicapped leagues, considered a form of cheating. See also dump and on the lemonade.

Chiefly American: The short rail at the foot of the table. Frequently used imprecisely, to mean foot cushion. Compare top rail; contrast head rail.

A line, sometimes imaginary (especially in American pool), sometimes drawn on the cloth, that runs horizontally across the table from the second diamond (from the head rail) on one long rail to the corresponding second diamond on the other long rail. In most pool games, the opening break shot must be performed with the center (base) of the cue ball behind the head string (i.e. between the head string and head rail). The head string intersects the long string at the head spot, and delimits the kitchen (and, in European nine-ball, the outer boundary of the break box). The head string's position is always determined by the diamonds, in contrast to the similar but different baulk line, the position of which is determined by measurement from the bottom cushion (head cushion).

Also yellow(s).
In snooker, the lowest-value colour ball on the table, being worth two points. It is one of the baulk colours.
In blackball, one of two groups of seven object balls that must be potted before the eight ball; compare stripes; contrast red ball.

Slang term for the cue ball.

Slang for the cue ball.

The Higher Education Snooker and Pool Council is a voluntary, not-for-profit organisation established to promote cue sports in institutions of higher education on the island of Ireland.

Describing a difficult pot: "the awkward cueing makes this shot missable."

A shot that has a positive outcome for the player, although it was not what the player intended. Examples of flukes include an unexpected pot off several cushions or other balls having missed the pocket aimed for, or perhaps a lucky safety position after having missed a pot. Compare fish and slop; contrast mark (sense 3) and call. It is customary to apologise to one's opponent if one does this.

A player who was not shooting well during a match but suddenly turns it around and starts playing better and more accurately. Also known as "Finding a stroke" or "Found their stroke".

Also spider rest. A type of rest, similar to a common American-style rake bridge but with longer legs supporting the head so that the cue is higher and can reach over and around an obstructing ball to reach the cue ball. See also swan.

The ACS Canadian affiliate organization, the Canadian Cue Sport Association.

This describes a shot where you bank the object ball off of a rail and then sink it in a corner pocket.

Oceania Pocket Billiard Association.

A particular shot where the object ball hits or grazes another object ball on the way to its pocket or toward hitting yet another object ball.

This refers to the distance of deflection that the ball comes off of the cue stick after a hit is applied with side spin on it.

This is an instance when the person not taking their turn interferes with the game play, this is recorded as a foul.