Semantics defines the meaning of words, signs & symbols.
Semantics is Just when a meaning has a definite balance. When semantics is just a matter of definition, it has no balance and no true meaning. When there is no true balance to the meaning, it is just a matter of how a word is defined.
When a word is defined with a balanced meaning, it just is semantically correct. Its meaning is in balance with its definition. When meaning is defined in an unbalanced way, it is semantically incorrect.
When semantics gives meaning both balance & definition, its meaning is definitely balanced & just.
Semantics is just when the intuitive emotional meaning is balanced with its rational intellectual definition. This means that I intellectually know it is right because it intuitively feels good.