stubborn person; strong-minded person; obstinate person
祖父は筋金入りのいごっそうだ。
My grandfather is a true stubborn man.
土佐にはいごっそうが多いらしい。
Apparently there are many stubborn people in Tosa.
あいつはいごっそうだから説得は無理。
He's so stubborn, persuading him is impossible.