What is the opposite of lightly?

The opposite of "lightly" depends on the context. Here are some possibilities:

If you're talking about weight or pressure:

* Heavily

* Strongly

* Forcefully

* Hard

If you're talking about intensity or degree:

* Heavily

* Strongly

* Deeply

* Seriously

* Intensely

If you're talking about a manner of doing something:

* Carelessly

* Roughly

* Harshly

* Vigorously

If you're talking about a feeling or emotion:

* Strongly

* Deeply

* Passionately

* Intensely

Example:

* Lightly: He lightly touched her cheek.

* Opposite: He forcefully pushed her away.

To choose the best opposite, consider the specific situation and what you want to convey.