"High and dry" is an idiomatic English expression meaning stranded, neglected or abandoned with no recourse. It is attested at least as early as the late 18th century. The phrase originates in nautical jargon, but has since become more general, referring to all cases of abandonment without hope of rescue. The full expression is usually "to be left high and dry."
The expression "high and dry" refers to a ship stranded on the shore. If a vessel runs aground at high tide, the tide will subsequently recede, leaving the vessel's hull above the water level. A vessel in this position, stuck on the shore and above the water, is impossible to move it off again until the next high tide. Complicating matters, sailing vessels were not constructed to be out of water for long periods, and could suffer damage due to exposure if stranded ashore. For this reason, something which is "high and dry" is in a hopeless position, without any chance of help.
The first recorded use of "high and dry" is of this nautical use. In 1796, The London Times reported that “The Russian frigate Archipelago, yesterday got around the Nore at high water, which; when the tide ebbed, left her nearly high and dry.” At some later point, the expression stopped being used literally to mean a ship that had run aground and began to be applied to an individual in a similarly unlucky predicament. Exactly when this transition began to happen is uncertain, but it is probably one of a large number of nautical expressions that entered common use in the early 19th century.
Usually, "high and dry" refers to a person placed in a hopeless situation by someone else's actions. It often has the specific meaning of someone or something abandoned partway through an undertaking. By analogy, the person who does so is like the water in the example of a ship, lifting the vessel into a dangerous position and then abandoning it. "Left in the lurch" is an expression with a similar meaning.
The phrase "high and dry" is widespread in popular culture. It is most notable as the title of a 1995 single by British rock band Radiohead, but it has also been used as the title of several other musical works, including a 1992 album by Definitely Leppard. It is so widely understood that it is frequently used by sources such as news networks, which generally try to avoid overusing idiomatic speech.