Endless energy or stamina.

Persistent effort without getting tired.

Unwavering determination and perseverance.

Relentless drive to keep going despite challenges.

Boundless enthusiasm and motivation for a task or goal

Unwavering energy; persistent effort without exhaustion.

Indefatigable, never tiring or showing signs of weariness.

Untiring dedication and relentless perseverance in tasks.

Enduring stamina and unflagging determination to succeed

. Relentless drive and unwavering commitment towards goals