ἰσχυρόν[2 verses](adj sg masc acc) "The strong man" is ischuros, which means, as an adjective, "strong," "mighty," and "powerful," "forcible," "violent," "severe," "excessive," and, as an adverb, "strongly, with all force, very much, exceedingly, from ischus, meaning "strength."  - "A strong man's" is from an adjective used as a possessive noun. It means "strong," "mighty," and "violent." So it means "of a strong one" or "of a violent one."