用釘子釘牢,使確定下來,要明確表態,使履行諾言
nail down v 1: succeed in obtaining a position; "He nailed down a spot at Harvard" [syn: {nail}, {peg}] 2: define clearly; "I cannot narrow down the rules for this game" [syn: {pin down}, {peg down}, {narrow down}, {narrow}, {specify}] 3: make final; put the last touches on; put into final form; "let's finalize the proposal" [syn: {finalize}, {finalise}, {settle}]