Expression: "to nail down"

[Foma]

English Language Tests, Intermediate level

ESL/EFL Test #723 "Real Life: Using Body Parts as Verbs (3)", question 1

We don't have much time left. We really have to ......... down a decision soon.

(a) nose
(b) knee
(c) arm
(d) nail

English Language Tests, Intermediate level

ESL/EFL Test #723 "Real Life: Using Body Parts as Verbs (3)", answer 1

We don't have much time left. We really have to nail down a decision soon.

Correct answer: (d) nail
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what does nail means?

Foma

[Kitosdad]

Good morning Foma. The statement is being made that a decision HAS to be arrived at.

" Nail down " means to be decisive, and come to a decision. ( In this case. )
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