Only after a bona fide Beis Din held a trial with both the husband and wife present in the courtroom (as halachicly no Beis Din trial can be held without the presence of both parties to the dispute). And after having completed said trial, a majority of the three Dayanim ruled l’halacha that the husband is obligated to give a Get even if he wishes not to.
Note that normatively, by default, the halacha is that he does not have to give a Get if he doesn’t want to give it. There are only rare halachic circumstances which is deemed under halacha as valid “cause” obligating him to give it against his will.
If all the above conditions have been met and proven in Beis Din, and the Dayanim so rule, and he yet refuses to give it after being ordered to do so by the Beis Din, then and only then is he a halachic get refuser.
Also note that if one of the parties to the dispute refuses to show up in Beis Din, that party is in contempt of Beis Din (with the requisite negative consequences of being in contempt.) Nevertheless, at that stage the party isn’t obligated to give a Get since the Beis Din trial to judge whether a halachic obligation to give it exists — or not — hasn’t yet occurred.