nonfunctional slack-fill

(noun).  This complex phrase is FDA legalese.  Found this one on a recent Planet Money episode on class action lawsuits.

Nonfunctional slack-fill is empty space in packaging that serves no purpose.  Potato chips, for example, have functional slack-fill in their packaging because the empty air in a potato chip bag protects the chips from pulverization. Nonfunctional slack-fill is when a seller deliberately deceives the consumer with excessive packaging.  As the Russian idiom goes, “all feathers, no fluff.”

Or, in academese, synonyms include: padding, fluff, filler, bullshit, and–at its worst–rhetoric.