Phenomenon where two balls, (usually the cue ball and an object ball ) have some foreign material (often residual chalk or dirt picked up from unbrushed cloth ) between them at the point of contact, resulting in the struck object ball being thrown offline from the expected trajectory, and often also affecting the post-impact path of the cue ball . A typical precaution against cling is to ask for the cue ball and/or object ball to be cleaned by the referee in order to remove chalk that is already on the ball prior to the shot . The table cloth should also be clean . However, no precaution can ward against cling resulting from chalk transferred from the cue tip to the cue ball during a single shot . Coincidental cling can therefore cause unpredictable play and occasionally lead to rudimentary shots being missed at even the highest levels of the game . "Cling" (and derived words like "clung", "clinger", "clinging", etc.) may be used as a mass noun, less commonly as a count noun, as a verb, and rarely as an adjective ("cling is annoying", "two clings in one frame ", "they clung", "unintentional cling shot ", respectively). Also known as skid , or in the UK, kick (sense 2). See also dead ball , sense 2.