Plural of energizer; people or things that provide energy, enthusiasm, or motivation (American spelling).
From energizer (American form of energiser) plus -s (regular English plural). The American -ize spelling is carried through the agent noun formation.
The Energizer brand so thoroughly colonized this word that when you see 'energizers' you might think 'bunny' first—a rare case where a trademark almost becomes the common word for the category.
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