strong, vigorous, powerful, muscular, hard, tough, stringy, athletic, sturdy
The boy had a sinewy back. Your welcome.
Michelle was slender and tough,with sinewy muscles.
muscular
The word "sinewy" is an adjective, used to describe something that is lean and muscular, with well-defined muscles.
Pertaining to, consisting of, or resembling, a sinew or sinews., Well braced with, or as if with, sinews; nervous; vigorous; strong; firm; tough; as, the sinewy Ajax.
I would suggest that "muscle" would be an antonym of sinew. Someone or something that is sinewy is "cut" and lean, so the opposite would be someone that is bulky, or muscular. I have, however, also seen "muscle" listed as a synonym of sinew.
sinewy, rough, wiry
loose; or yeah...i cant think of any more....bahahahahahahahahaha!
lean and/or sinewy
Sinewy and soft spring to mind...
strong
strong, vigorous, powerful, muscular, hard, tough, stringy, athletic, sturdy