な奴だ

is a ... guy/person; is such a ... person

→ だ

phrase Common #5,834

is a ... guy/person; is such a ... person 奴（やつ） is an informal, sometimes derogatory way to refer to a person. The な connects a な-adjective or noun-like modifier to 奴, as in 最低な奴だ (he's a terrible guy) or 陽気な奴だ (he's a cheerful guy).

JA: 私のボスは最低な奴だ。

EN: My boss is a terrible guy.

嘘のヘタな奴だな

You're a terrible liar.

— フィフス・エレメント (1997)

強欲な奴だ

What a greedy bastard.

— Брат 2 (2000)

トムは本当に罪な奴だと思う。

I think Tom is really a heartbreaker.

なんて強情な奴だ。

What a stubborn guy.