Antonyms of adj square-shouldered

1 sense of square-shouldered

Sense 1
big-shouldered, broad-shouldered, square-shouldered -- (having broad shoulders; "big-shouldered and heavy-armed")

INDIRECT (VIA robust) -> frail -- (physically weak; "an invalid's frail body")

Similarity of adj square-shouldered

1 sense of square-shouldered

Sense 1
big-shouldered, broad-shouldered, square-shouldered -- (having broad shoulders; "big-shouldered and heavy-armed")
       => robust (vs. frail) -- (sturdy and strong in form, constitution, or construction; "a robust body"; "a robust perennial")