This is the 9163rd most frequent Korean word.
걱을
It seems there may be a typo in the word "걱을." If you meant "걱정," it translates to "worry" or "concern" in English. If this is incorrect, please clarify.
In this sentence, '걱정을' (merged form of '걱정' and the object marker '을') refers to worry or concern, indicating the noun usage of '걱정' in direct relation to '키웠다' (increased)
그는 할 일을 미루면서 걱정을 키웠다.
He postponed his tasks and increased his worries.
Here, '걱정하지' uses '걱정' to express a state of worrying or not worrying. It combines with '-지 않다' to negate the action of worrying.
새로운 도전에 대해 전혀 걱정하지 않습니다.
I have no worries about the new challenge.
In this sentence, '걱정이' indicates the noun '걱정' in subject position, used with '-이 되다' to express the state of becoming worried.