Striven is the past participle of strive, which means to try very hard to do something.
Striven makes people think of working very hard to do something, even if it is difficult.
Examples:
She has striven to be the best in her class.
He has striven to make his parents proud.
They have striven to achieve their goals.
The little ant has striven to carry the big leaf.
The hero has striven to save the town from the dragon.
The team has striven to win every game this season.