1Fat or thick; having considerable girth or a large diameter/width.
その木の幹はとても太い。
The trunk of that tree is very thick.
ケーブルが太くて丈夫だ。
The cable is thick and sturdy.
指が太いので、小さなリングは入らない。
My fingers are thick, so a small ring won't fit.
このパスタは太い麺を使っている。
This pasta uses thick noodles.
2A deep, thick (sonorous) voice; low-pitched and resonant sound quality.
彼は低く太い声で話すのでよく聞き取れる。
He speaks in a low, resonant voice, so it's easy to hear him.
その歌手は太い声が特徴だ。
That singer is characterized by a thick (sonorous) voice.
3Daring, shameless, or brazen; describes a bold, unashamed attitude (colloquial usage, often as 太い神経 'thick nerves').
人の物を勝手に使うとは、ずいぶん太い神経をしている。
Using someone else's things without asking — he really has some nerve.
借りたお金を返さないなんて、太い奴だ。
Not paying back money he borrowed — what a shameless guy.