be short of, not have, be deficient in, need, require
be without
Inaction??
incommunicado
Lack, want,
lack dearth
lethargic
Harsh truth
lacking skill
Lazyness
to lack to deprive to sacrifice
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.
Another word for want is long. You can also go to www.thesaurus.reference.com for other synonyms.