Which summoner spell allows you to quickly move a short distance in a direction? Flash does.
Flash is a summoner spell that instantly blinks a champion a short distance toward a chosen location. Players use it to escape a gank, cross a wall, close the gap for an attack, dodge a crucial ability, or reposition during a team fight. Because it is instantaneous, it is one of the most important defensive and offensive tools in League of Legends.
Flash has a long cooldown, so using it is a major strategic decision. A player who spends Flash to secure a kill may be vulnerable until it returns, while holding it can deny an enemy an easy engage. Flash can also interact with champion abilities: for example, champions may combine it with crowd-control skills to create sudden, difficult-to-react-to plays.
The alternatives in this question perform different jobs. Ignite applies damage over time and reduces healing, Teleport moves a champion to an allied structure or unit after a channel, and Ghost grants sustained movement speed rather than an instant blink. Flash is therefore the single canonical answer to the short-distance directional-movement description.