impotent
lacking strength or power
impervious
incapable of being penetrated or affected
in-, im-
not
redoubtable
arousing fear; formidable; awesome
predominant
most important
brawn
muscular strength
bastion
stronghold, fortress
impregnable
unable to entered by force
indomitable
unable to be conquered
domit
lord
efficere
to effect
bulwark
a strong defense
formidable
awesome; hard to overcome; dreadful
potent
strong and effective
stalwart
physically or morally strong person; strong supporter
efficacious
capable of producing a desired effect
potens
strong
robust
full of vigor