There was a downfall.
It was King Peter's downfall.
The downfall of the city.
The market experienced a downfall.
Yes you can, but I think you would usually use this word in a past sentence or maybe a future sentence: past - Alcohol led to his downfall present - Alcohol will be his downfall
He went downfall as he fell of the cliff.
The demise of his father brought a downfall on their livelihood.
The actions of the people during the downfall of Communism was iconoclastic.
Natural selection may ultimately be his downfall.
Greed is the downfall of many corrupt politicians.
She felt a strong compulsion to check her phone constantly for messages.
I do not condone the use of sadism in any context, as it involves deriving pleasure from inflicting pain or suffering on others, which is unethical and harmful.
To this day, historians argue over what caused the Roman empire's downfall.
She has a retentive memory, able to remember even the smallest details of past events.
use it by saying- how can you use the word ebullient in a sentence?
I can't believe you would have the audacity to ask me anything.I am appalled at your audacity.Your audacity will be your downfall.