closest
adj. A1 Beginner US //ˈkɫoʊsəst// UK //klˈəʊsəst// clos·est
adj. the shortest distance away from something in space or time. It also describes the person you know best and like most.
adj. the superlative form of close, indicating the least amount of distance, time, or relationship between two points or people.
The closest grocery store is just around the corner.
Even though they live in different countries, she remains his closest friend and confidante.
The scientists monitored the asteroid as it reached its closest point to Earth, ensuring that its trajectory posed no threat to the planet.
Usage
Typically used with the definite article 'the'. When describing relationships, it implies a high degree of intimacy or trust.