Well for instance, you can have a relationship with a relation, but probably not the other way 'round. Have you looked these words up in a dictionary?
– JHCLNov 06 '15 at 11:53
(I've reworded your query about the suffix. Let me know if this wasn't your meaning.)
– JHCLNov 06 '15 at 11:59
A "relation", in one sense, is someone who's related to you -- brother, cousin, etc. A "relationship" (in the most similar sense) is a business or social "bond" between two entities -- people, companies, etc.
– Hot LicksNov 06 '15 at 12:41
Welcome to EL&U. I posted a link of a related question in the above comment. If you don't find it satisfactory, please edit your question to be more specific. Thanks.
– Nov 06 '15 at 13:03