Is it ungrammatical to say Nがなく instead of Nなく when it means "without N"?


The phrase Nなく means "without N" and is used to modify verbs, as in:

> 彼は私を躊躇なく殴った。  
>  He hit me without hesitation.

In sentences like this, is it ungrammatical or unnatural to say Nがなく instead
of Nなく?




> In sentences like this, is it ungrammatical or unnatural to say Nがなく instead
> of Nなく?

Basically, yes. The role of `<Noun>なく` is explained in the
[answer](https://japanese.stackexchange.com/a/59614/7705) linked in
Chocolate's comment, but what's important here is that it behaves like an
adverb.

Generally if you say `<Noun>がなく`, you are making a statement and `ない` is the
verb. This `なく` is functionally equivalent to `なくて`, in the sense that the
conjugation here just allows the sentence to continue.

You have

> 彼は私を躊躇なく殴った。
>
> He hit me without hesitation.

You could also have

> 彼は躊躇がなく、私を殴った。
>
> He had no hesitation, and hit me.

which is technically grammatical, though it sounds awkward (as does the
equivalent English), and people reading it may just think you wanted to say
`躊躇なく`.

This

> 彼は私を躊躇がなく殴った。

is just confusing and likely ungrammatical; I wouldn't know what to make of
it.

