What is a synonym for science-?

There isn't one perfect synonym for "science" as its meaning is quite broad. However, depending on the context, you could use words like:

General:

* Knowledge

* Learning

* Research

* Study

* Inquiry

* Scholarship

* Methodology

Specific to a particular field:

* Biology

* Physics

* Chemistry

* Astronomy

More informal:

* Know-how

* Expertise

Formal:

* Epistemology

* Systematized knowledge

Ultimately, the best synonym will depend on the specific context of your writing.