on the nose is an adjective and adverb meaning "being precise with regard to a prescribed or specified criterion". It carries 2 recorded senses.
being precise with regard to a prescribed or specified criterion
“his guess was on the nose”
“the prediction for snow was right on the button”
Definitions, synonyms and semantic relations for on the nose come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.