ad unguem

Calque of Ancient Greek εἰς ὄνῠχᾰ (eis ónukha, literally “to a nail”): an expression borrowed from sculptors, who, in modelling, give the finishing touch with the fingernail, or from joiners, who test the accuracy of joints in wood by the fingernail.

• (Classical) IPA^(key): /ad ˈun.ɡʷem/, [ad ˈʊŋ.ɡᶣẽ]

ad unguem (not comparable)

1. to a hair, to a nicety, precisely, exactly, with great exactitude, to an exact measurement or standard, perfectly

• in unguem

• unguis · I.B.5 in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “unguis · 1.b” on page 2,093/1 of the Oxford Latin Dictionary (1st ed., 1968–82)