These concepts usually only define certain aspects of the legal validity concept, with the disadvantage of limitations on the concept extension and mechanicalness of the concept connotation.
Nevertheless, the word 'amateur' does carry a connotation that the person concerned is not fully integrated into the scientific community and, in particular, may not fully share its values.
This is where teachers of English might helpfully note the difference between denotation (dictionary meaning) and connotation (associations that may not be part of a formal definition).
The very word philanthropy does not necessarily have 100% positive connotations for the public at large given where we are in terms of the public's attitude towards business or the banks and that kind of stuff.
How the words go together, how to use them correctly within a grammatical structure, and how to understand the nuance or the connotation when that word is used.