This is the 17987th most frequent Korean word.
수비수의
"Defender's" (possessive form related to a defender).
Here, '수비수의' modifies '역할' to indicate ownership or association with the defender's role.
수비수의 역할은 공격을 막는 것입니다.
A defender's role is to block attacks.
In this sentence, '수비수의' modifies '결정' to denote the decisions made by the defender.
팀은 수비수의 결정을 존중해야 합니다.
The team should respect the defender's decisions.
Here, '수비수의' describes '위치' to specify whose position is referred to, i.e., the defender's.