No longer active or effective, very sick, close to failure or death
1) That actor is trying to revive his moribund career.
2) The peace talks are moribund.
From Latin moribundus or mori which means 'to die'.
dying, at death's door, perishing, succumbing, fading, expiring, stagnant, decadent, inert, dormant
active, thriving, animated, lively, spirited, nascent, frisky, flourishing, booming, dynamic, sprightly