“+ adjective
Etymology: un- (I) + sustained, past participle of sustain
: not sustained: as
a. obsolete : not physically sustained or supported
b. : not kept up or supported by some aid
leaving the station feeling empty and unsustained — S.H.Adams
unsustained any longer by loans, the business failed
c. : not kept or continued at a consistently high level
a convolution of plots makes for unsustained interest — Current Biography