illegible
incomprehensible
uncomprehensible
catatonic
faraway
foolproof
frictionless
handwritten
inaudible
indistinguishable
loopy
masterless
portionless
soundproof
subsonic
uncial
undefended
undetectable
uninhabitable
unintelligible
unnoticeable
unobtainable
unopposed
unreadable
unrecognizable
unusable
valueless