closest Add to list Definitions of closest adverb (superlative of `near' or `close') within the shortest distance Find a gopost location near you. Contract Postal Units (CPUs) are located within existing businesses. While not freestanding Post Office locations, CPUs provide a full range of USPS retail products and services at regular USPS prices. A few kiosks are in large shopping malls. Define closest. closest synonyms, closest pronunciation, closest translation, English dictionary definition of closest. adj. clos·er , clos·est 1. Being near in space or time. close suggests keeping a tight grip on one's money and possessions. niggardly implies giving or spending the very smallest amount possible. The concept of proximity and nearness has always been essential in human interactions and relationships, making 'closest' a commonly used term in various contexts. to stop or obstruct the entrances, apertures, or gaps in: He closed the crate and tied it up. The term closest generally refers to being nearest in proximity or distance relative to other objects or locations. It implies the minimal amount of space or time required to reach something or someone. Synonyms for CLOSEST: nearest, nearby, approximate, adjacent, next-door, near, immediate, close; Antonyms of CLOSEST: apart, single, farthest, separate, isolated, nonadjacent, far, noncontiguous Find local businesses, view maps and get driving directions in Google Maps. The superlative form closest is used when comparing more than two entities, highlighting which one is nearest or most similar. Example 1: Of all the planets, Venus is the closest to Earth. .