In a heavy manner.
He clomped heavily up the stairs in his boots.
With a great weight.
heavily burdened
To a considerable degree, to a great extent.
He drank heavily.
In a manner designed for heavy duty.
heavily armed soldiers; heavily armoured tanks; heavily reinforced walls
So as to be thick or heavy.
heavily built young men; his heavily muscled arms
In a laboured manner.
he breathed heavily