na-adjective
insane; fanatic; madly enthusiastic
Describes a person, behavior, or attitude that is extremely passionate or obsessive to the point of seeming crazy. Often used in compounds like 狂的なファン (fanatical fan).
彼は狂的なまでに仕事に打ち込んでいる。
He is fanatically devoted to his work.
その歌手には狂的なファンが多い。
That singer has many fanatical fans.
Compound of 狂 (kyō, 'madness') and the adjectival suffix 的 (teki, '-like'). The exact historical derivation is uncertain, but the word follows a common pattern for forming adjectival nouns from nouns.