Does the lack of a universal definition of art allow for art to be subjective? In other words, can something be art to me, but not to someone else?

First I'm not sure that when people say that they do not consider something art, that they in fact mean what they say. I think some of cases what people mean when they say that something is not art is that it is not good art according to their taste. Also, I think that what tends to happen sometimes is that people say they do not like things simply because they do not fully understand them.I personally do not a agree that simply because we cannot come to a universal definition on something that this thing then comes subjective. It just means that the definitions which we have are no fully adequate, and that they still need to be refined. There are common conceptions of things which are not art, and although this may not be a helpful argument as to what is art, it could be a starting point. I do admit that art does contain qualities which are subjective such as beauty, however, the presence on such qualities is not what defines art as being art. I think that part of the difficulty with defining art is that, art is in part a mode of expression and thus in constantly developing or growing as are those individuals who create it.

If it's true that art expression is ever changing then can we ever come up with a concrete definition of it?