Sliding or falling back; marked by a relapse or return to a former worse state.

adjective. Marked by a relapse; falling back; tending to return to a former worse state.

adjective. an acute, epidemic, contagious fever, which prevails also endemically in Ireland, Russia, and some other regions. It is marked by one or two remissions of the fever, by articular and muscular pains, and by the presence, during the paroxism of spiral bacterium (Spirochæte) in the blood. It is not usually fatal. Called also famine fever, and recurring fever.

noun. relapse

verb. Present participle of relapse.

noun. a failure to maintain a higher state

"There are different types of -- that we call the relapsing remitting then the secondary progressive where there is an ongoing weakness or a progression of symptoms."

relapsing fever  

failure  

recidivism  

collapsing  lapsing  

relapse