dodderer:
(plural: ‘dodderers‘; pronunciation: for the right pronunciation of this word, please click here)

a dodderer
a person who shakes and trembles, usually from old age;
person who looks weak and feeble from old age;
a person who makes slow and unsteady progress in doing something,

a dodderer --- an extremely slow worker with lot of pending work
Mohammed Ali, once a strong heavy young man who knocked out any heavy weight boxers of his time, is now a mere dodderer as a result of a brain disease called Parkinson’s disease.
A senior politician in a political party who is slow to understand a policy or slow to get to his point of view is called an (old) dodderer and a junior politician who is too fast or too aggressive in venting out his/her opinions is called a maverick or firebrand.
It has been found out that more and more people are becoming dodderers before the actual age due to reasons unknown, and health experts point to environmental pollution as the chief cause.
Some senior citizens make a pretence of being dodderers to get things done for them though they are not actually incapable of doing those things themselves!
