What does it mean to be a holistic practitioner?

Many Meanings. The meaning of holistic practitioner depends on how the practitioner defines him or herself. May mean that they use both natural and pharmaceutical therapies. It could mean that they only use natural therapies. It could mean that they evaluate both mind and body of patient. They maybe a doctor, or might not. Since there are so many variables, it is important to be an informed patient.
Treats the whole pt . Holistic implies that the complete individual is treated, not just the disease. That is, the stress, living situation, nutrition etc are taken into consideration when treating , say, the flu. This can be a good thing. Problem is it opens the door to many intuitively hoped-for but scientifically unproven theories such as ' energy imbalances or imaginary toxins., etc. Check http://NCCIH.nih.org.