na-adjective
Slang term for something oily or greasy, often used for skin, hair, or food. Has a negative, exaggerated feel.
このピザ、脂ギッシュすぎて食べられない。
This pizza is too greasy to eat.
彼の
His face is always oily.
na-adjective
Slang for a person who is annoyingly persistent or pushy. Often used for someone who won't take no for an answer.
あの営業マンは脂ギッシュで、断っても何度も電話してくる。
That salesman is so pushy; he keeps calling even after I said no.