Slacks implies pants of certain materials which are not part of a suit (jeans are not slacks, and you would not refer to the pair of trousers that came with a suit as slacks.) It is also more common to use slacks to refer to pants worn by women, while men would wear trousers.
Health care safety net providers are those that have a legal mandate or mission to offer medical care to all patients, regardless of their ability to pay, and have a substantial number of patients who are uninsured or on Medicaid.
Uninsured motorist (UM) coverage provides coverage if you are in an accident and the other driver is both legally responsible for the accident and is not insured. It is an addition to a standard auto insurance policy that is required in some states and optional in most others.