This is the 6874th most frequent Japanese word.
ヘトヘト
Completely exhausted; worn out.
ヘトヘト expresses physical and mental exhaustion from completing the exam.
試験が終わってヘトヘトになった。
I became completely exhausted after the exam.
ヘトヘト is used to describe the state of tiredness after an exhausting activity like playing.
子供たちと遊んだ後でヘトヘトだ。
I feel extremely tired after playing with the children.
ヘトヘト here emphasizes the communal exhaustion felt by the group after an overwhelming event.