I've never heard of the term "virile"
Me too, until I tried to translate "męskożywotny" ;)
Maybe I'm using wrong English definition. If that is the case, maybe somebody here know what is the right translation of męskożywotny.
I think you are using that term rather loosely
and I think the same about your usage of declination.
Even if some nouns have the same form in different cases, they are still declinated. In the case of "psy" you have to know the meaning of sentence to know which case was used: nominative or accusative. Then you can determine the role of word in sentence: subject or indirect object.