Etymological Wonder

From Chambers Dictionary Of Etymology:

Stevedore: n. person who loads and unloads ships. 1828 (in 1788 stowadore), American English; borrowed from Spanish estibador, one who loads cargo, from estibar, to stow cargo, from Latin stipare pack down, press; see STIFF-v. 1862, American English, to load and unload a ship; from the noun.

I wonder where we get 'stiff', as in 'a bunch of working stiffs.' Is it from this word, or is it from the 'stiff' sense used for corpses? The dictionary doesn't say.

I love the word stevedore. Had to look it up in high school, reading something in English class that I can't remember now, which is a pity. Maybe it was Herman Melville.