Let's try out some definitions randomly pulled off the internet:
Falsifiability or refutability of a statement, hypothesis, or theory is an inherent possibility to prove it to be false.
What is an inherent possibility? I have no idea. Perhaps the idea is that the statement (etc.) is one that is contingently true. Let's try another....
A falsifiable claim is one for which there is some observation (or set of observations) we could make that would show us that the claim is false.
"The earth travels around the sun." That's true. Is there some observation we could make that would show us that the claim is false? How could a true statement be shown to be false?
Falsifiability or refutability is the logical possibility that an assertion could be shown false by a particular observation or physical experiment. That something is "falsifiable" does not mean it is false; rather, it means that if the statement were false, then its falsehood could be demonstrated.
This definition seems too strict. Some theories can't be shown false by a particular observation or experiment but only by many. Nonetheless it's an improvement on the previous definitions. "The earth travels around the sun." That's a contingently true statement (there are possible worlds where the earth doesn't travel around the sun). But if the statement were false, the falsehood could be demonstrated by observations or experiments.
Still there are problems. Theories in physics are heavily dependent on math and mathematical propositions are either necessarily true or necessarily false. Part of scientific theories include mathematical propositions. But (most) mathematical propositions can't be falsified by observation or experiments (save things like Euclid's parallel postulate).
Perhaps, though, mathematical propositions aren't scientific. And perhaps theories are scientific just so long as they have SOME falsifiable propositions in the sense above.
But creation science has some falsifiable propositions, some propositions which scientists think ARE false and can be shown to be false. Such scientists shouldn't think creation science isn't science because of the falsifiability criterion, but should think it's bad science.