No doubt there are a hundred others like them, but two that occur to me at the moment are:
A LIFE INSURANCE POLICY, that relies for its existence on what it refuses to name, namely death.
THE DEPARTMENT OF DEFENSE, which likewise refuses to name what it gaily promotes, namely war. (The "War Department" had a healthy and more forthright run from 1789 to 1947. The "Department of Defense" became the new moniker in 1949.)
Lesser luminaries include the latter-day "issue" to replace the blunt-force-trauma of a "problem" and the always-soothing "procedure" to stand in for an "operation."
Yes, Virginia, it's true: Shit doesn't stink.