Most closely related

• Handiest resolute knight sent to the front
• Least distant
• Most local
• Most convenient
• Like a relative notified in an emergency, maybe
• Eastern (anag)
• Supremely neighboring
• Johnny Cash: "You're the ____ Thing to Heaven"
• Like a scoring ball in bocce, vis-à-vis the jack

Wiktionary Word definitions in Wiktionary
a. Closest to, (en-superlative of: near ). prep. closest to