This is the 4854th most frequent Japanese word.
激辛
Extremely spicy.
In this sentence, 激辛 is used as a noun referring to extremely spicy dishes or flavors.
激辛を挑戦するのは勇気が必要です。
Challenging extremely spicy food requires courage.
Here, 激辛 is used as an adjective to describe the spiciness level of the curry.
このカレーは激辛で有名です。
This curry is famous for being extremely spicy.
激辛 is used as an adjective modifying 味 (flavor) to describe the type of flavor that is liked.