This is the 308th most frequent Korean word.
강력한
"강력한" means "powerful" or "strong" in English.
Here, '강력한' is used to describe '의지' (will), meaning that the will is very strong or powerful.
그는 강력한 의지를 가지고 목표를 이루었다.
He achieved his goal with a strong will.
In this sentence, '강력한' modifies '폭풍' (storm), indicating that the storm is very intense or forceful.
강력한 폭풍이 해안을 휩쓸었다.
A powerful storm swept the coast.
Here, '강력한' is describing '관계' (relationship), signifying a close or solid relationship.