unsturdy (?.)

• abortive
• bootless
• crumbling
• decrepit
• disintegrating
• failed
• failing
• fruitless
• futile
• ineffective
• ineffectual
• inefficacious
• infirm
• lame
• manque
• miscarried
• miscarrying
• of no effect
• poor
• poorish
• rotten
• rotten at
• stickit
• stillborn
• successless
• unfirm
• unfortunate
• unsolid
• unsound
• unstable
• unsubstantial
• unsuccessful
• useless