A priest can indeed, and sometimes must deny Communion:
CIC 915. Those who have been excommunicated or interdicted after the imposition or declaration of the penalty and others obstinately persevering in manifest grave sin are not to be admitted to holy communion.
The canon uses the passive voice, but it does not say they “are not to present themselves,” but that they “are not to be admitted,” i.e. by the priest.
But yes, it can be absolved, so long as the offender is sorry and willing to stop. Go to Confession. If the priest has not the authority to absolve, he will let you know what must be done. Off the top of my head I don’t know which offenses are reserved to bishops, and which to the Holy See.