Bhakta means who has dedicated his life to serve Kṛṣṇa. That is bhakta.
- sarvopādhi-vinirmuktaṁ
- tat-paratvena nirmalam
- hṛṣīkeṇa hṛṣīkeśa-
- sevanaṁ bhaktir ucyate
- (CC Madhya 19.170)
This is bhakti definition. When one becomes freed from all designation. "I am American." This is designation. "I am Indian." This is designation. "I am brāhmaṇa." This is designation. "I am kṣatriya." This is designation. So one has to become free from all designation. This designation is bodily. I am not this body. Ahaṁ brahmāsmi. I am spirit soul. Therefore when one understands that "I am not this body, I am spirit soul, I am part and parcel of the Supreme," that is self-realization.