NOTE: I am not a Groovy expert.
There appears to be two ways to use Groovy: pre-compiled ("compiles straight to
Java bytecode so you can use it anywhere you can use Java") and dynamically-compiled (generating bytecodes on the fly while interpreting Groovy source).
Pre-compiled Groovy might work on Android, but the Groovy-generated .class files would need to be integrated into the Android build process so they can be converted to Dalvik VM bytecode.
Runtime-compiled Groovy would work only if Groovy were taught how to generate Dalvik VM bytecode.
If there is pure interpreted mode for Groovy, where it does not attempt to generate bytecode at runtime, that might work as an embedded scripting language.