Antonyms of adj hardbound

1 sense of hardbound

Sense 1
hardbacked, hardback, hardbound, hardcover -- (having a hard back or cover; "hardback books")

INDIRECT (VIA backed) -> backless -- (lacking a back; "a stool is a backless and armless seat")

Similarity of adj hardbound

1 sense of hardbound

Sense 1
hardbacked, hardback, hardbound, hardcover -- (having a hard back or cover; "hardback books")
       => backed (vs. backless) -- (having a back or backing, usually of a specified type)