Heavily means to a great degree or with great weight and force. When snow falls heavily, it comes down thick and fast, piling up quickly on sidewalks and rooftops. When someone breathes heavily after running hard, their chest heaves up and down as they gulp air. When rain falls heavily, it pounds against windows and floods the gutters.

The word suggests intensity or burden. A backpack packed heavily with textbooks weighs down your shoulders. A team that loses heavily gets beaten badly, perhaps 45 to 10. Someone who relies heavily on their calculator for math depends on it so much they'd struggle without it.

You can hear the weight in the word itself. Actions done heavily are substantial, forceful, or extreme. When an author's writing is heavily influenced by Shakespeare, that influence shapes nearly everything they write. When a neighborhood is heavily wooded, trees dominate the landscape, covering it densely from edge to edge. The word tells you that whatever it describes is powerfully, noticeably, overwhelmingly present.