noun or participle which takes 'suru'
agonize; worry intensely
A direct loan from English, used in Japanese to mean struggling mentally with a difficult decision or feeling deep distress. Often used in casual or colloquial contexts.
進路のことでアガナイズしている。
I'm agonizing over my career path.
彼は小さなミスでもアガナイズするタイプだ。
He's the type who agonizes over even small mistakes.
Borrowed from English 'agonize', likely entering Japanese through media or casual speech. The exact date of borrowing is uncertain.