Another word for "lack of interest" is apathy or indifference. These both basically refer to a person who is uninterested, unresponsive or impassive. Another word to describe this sort of person could also be perfunctory.
Unresponsiveness is another word for lack of response. Lacking alertness or staying silent can also mean the same thing as lack of response.
Apathy
be without
Lack, want,
lack dearth
lethargic
incommunicado
Inaction??
Lazyness
lacking skill
Harsh truth
Another word for revival or renewed interest on something is the word renaissance. This is why the word renaissance was used in Europe when art and literature was under a classical influence.
The word is interest charged on capital.