Answer: mightiest

AnswerCrossword Clue
MIGHTIESTHaving the greatest power.
MIGHTIEST"Ere the ... Julius fell"
mightiestMIGHTY, strong (having great strength)
mightiestVery large
mightiestPossessing great and impressive power or strength, esp on account of size
mightiest(of an action) Performed with or requiring great strength