Badass, Iron Man, Macho Man, Tough Guy
Noun
てつじん
うちの社長は、鉄人すぎます。
My company president is way too much of a macho man.
わたしが一番すきな番組はりょうりの鉄人です。
The TV program I like most is Iron Chef.
私はスーパーで赤ちゃんに「いないいないばぁ」をしている鉄人を見た。
I saw a tough guy playing peak-a-boo with a baby in a grocery store.
A man made of iron is a strong man... aka a huge badass. Have you seen "Iron Chef?" The Japanese translation is 料理の鉄人, which means "Chef Iron Man" aka "Chef Badass," at least in my book.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.