Superlative form of close: most close..(adjective)
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Use "closest" in a sentence
"If I needed any help, the closest is about 20 miles away."
"COMPOUNDS: Add an apostrophe or ’s to the word closest to the object possessed: the major general’s decision, the attorneys general’s request."
"What he calls the closest approximation occurs in Section 16 of the original act, which authorized the issuance of Fed notes that shall be redeemed in gold on demand at the Treasury Department of the United States, or in gold or lawful money at any Federal Reserve bank."