Dharmic simply means ... that which leads you towards God, (or moksha, in the Hindu case) and adharma means that which leads you away from God (or delays you on the path to moksha)
Dharma/adharma is complicated, and is necessarily vaguer than good/evil, and seems to hit a wider range of possibility. Good/evil seems simplistic, like George Bush's 'you're either with us or against us'. It leaves little room for the more complex 'leaning towards' ideas that are all somewhere in the middle. A lot of actions have both factors in them. I don't think you can say something is good or evil, dharmic, or adharmic without closer inspection. Take murder, for example. If a person is mentally ill, and that disease causes delusions, is it evil? Even our justice society accepts the plea of insanity. But many folks would make the blanket statement that murder is evil. (Extreme example I know)
It may well just be language though, and it most like varies widely by individuals regardless of the terminology.