A man can be a perfect gentleman, or a perfect jerk.
I find the definition of “perfect” as “without defect” unobjectionable. I think it is consistent with your examples, as well. You use “perfect” attributively, which is to say not as a predicate in itself (as in “x is perfect”) but as a modifier of another predicate (“x is a perfect P”). If a man is a perfect gentleman, then he lacks nothing that a gentleman ought to have; he is without defect with respect to being a gentleman. If a man is a perfect jerk, then he lacks nothing that a jerk “ought” to have; he is “without defect” with respect to being a jerk. The latter usage is more attenuated, but that is because when we say that someone is a “perfect jerk” we are being ironic. Being a jerk itself is regarded as a defect, so it’s odd that we suggest that someone is a “perfect” jerk; he does everything he needs to be a jerk (but that end is undesirable in itself).
What about when we say unqualifiedly that a man is perfect? Well, the issue would be clearer if we give the man a name: Tom. So here to say “Tom is perfect” is to attribute “perfect” to Tom under a sortal: “Tom is a perfect man.” (The sortal, “man” in this case, will be the concept under which Tom chiefly falls, unless something else is specified by context. So if the preceding discussion had to do with who would be a good doctor to perform a surgery, then it would be reasonable to read “Tom is perfect” as “Tom is a pefect doctor”–he doesn’t lack any of the qualities which you’d want your doctor to have, though he may lack some of the qualities a man in general ought to have.)
This is why perfection is one of the transcendentals. It is an analogous predicate that depends on the form of what it is predicated of. God does not have a form in the sense that created things do (or rather, God does not have an essence given by form distinct from existence), so to say “God is perfect” is to say that God unqualifiedly is without defect. (A man is perfect if he does not lack anything that a man is supposed to lack. But his essence, specifying his potentialities qua man, still limits the exercise of his activities, so he is not absolutely perfect as God is.)