The first intransigent problem with trying to define a particular way of being (i.e. Republican or Democrat, conservative or liberal or libertarian, Catholic or Muslim or atheist, etc.) is that immediately you have others pushing on the boundaries of the definition. Definitions are definitively not static. They change in realtime, morphing into new ideological spaces organically—ironically beyond the control of those who seek to fix concepts with a clear definition. A conservative today was not a conservative 50 years ago. A liberal today was not a liberal 50 years ago. A farmer today was not a farmer 50 years ago. A feminist today was not a feminist 50 years ago. None of these definitions today fits their original definition exactly. Some are radically different.
The second irreducible problem with trying to define a particular way of being is that individuals can be defined in a multiplicity of ways and those ways can often appear to contradict one another. A liberal Republican, for instance, or a feminist Catholic. Interestingly, these very states of seemingly contradictory ways of being serve to alter the definitions.
None of these observations helps us solve the intractable problem of ever-evolving definitions, but it does help to provide a perspective on their elasticity. More importantly for me they help me understand that a definition is merely a starting point when it comes to understanding others, whether they have defined themselves or have been defined, and that even the definition is fraught with meanings that may or may not encompass what I understand the definition to mean.
I suppose this is one of those things that makes people so interesting and surprising—they are generally too dynamic to be contained by fixed concepts, so the concepts must either change or become irrelevant.