Holiness is a type of general refinement, perfection, and exaltation, not necessarily limited to one particular point or area.
Holiness here that there are certain acts that are so foul that one embarrasses not only himself, but God as well upon committing them.
When one refrains from committing a transgression, it may be because one simply has no desire to commit such an act.
In contrast, it may be that one is able to refrain from committing the transgression despite his desires.
The Midrash articulates this line of thinking: “I do have a desire for such and such, but what can I do, since my Father in heaven has ordered me to abstain?” (Sifra, Kedoshim 9).
The general conception of holiness is, in a certain sense, “I have no desire” -I cannot do it; I have an aversion to such a thing; it is simply out of the question for me to stoop to such a base, low level and commit such a sin.
A story is told of a rebbe who claimed regarding one of his Hasidim that the reason he does not sin is simply pride.
For this Hasid, it seemed degrading that an exalted personality such as he should demean himself through sin.
–Rabbi Adin Steinsaltz