SB (6.2.14) indicates that the chanting of the HK maha-mantra, even in joking, in the course of ordinary discussion, in indicating something extraneous, or in negligence, is called namabhasa, which is chanting that is almost on the transcendental stage

Expressions researched:
"Śrīmad-Bhāgavatam, Sixth Canto, Second Chapter, verse 14, indicates that the chanting of the Hare Kṛṣṇa mahā-mantra, even in joking, in the course of ordinary discussion, in indicating something extraneous, or in negligence, is called nāmābhāsa, which is chanting that is almost on the transcendental stage"

Sri Caitanya-caritamrta

CC Adi-lila

Sometimes demoniac nonbelievers, not understanding the potency of the holy name, make fun of the Vaiṣṇavas when the Vaiṣṇavas chant the Hare Kṛṣṇa mahā-mantra. This joking is also beneficial for such persons. Śrīmad-Bhāgavatam, Sixth Canto, Second Chapter, verse 14, indicates that the chanting of the Hare Kṛṣṇa mahā-mantra, even in joking, in the course of ordinary discussion, in indicating something extraneous, or in negligence, is called nāmābhāsa, which is chanting that is almost on the transcendental stage. This nāmābhāsa stage is better than nāmāparādha.

CC Adi 17.200, Translation and Purport

“‘Since that time, my tongue also always vibrates the sound “Hari, Hari.” I have no desire to say it, but still my tongue says it. I do not know what to do.’

Sometimes demoniac nonbelievers, not understanding the potency of the holy name, make fun of the Vaiṣṇavas when the Vaiṣṇavas chant the Hare Kṛṣṇa mahā-mantra. This joking is also beneficial for such persons. Śrīmad-Bhāgavatam, Sixth Canto, Second Chapter, verse 14, indicates that the chanting of the Hare Kṛṣṇa mahā-mantra, even in joking, in the course of ordinary discussion, in indicating something extraneous, or in negligence, is called nāmābhāsa, which is chanting that is almost on the transcendental stage. This nāmābhāsa stage is better than nāmāparādha. Nāmābhāsa awakens the supreme remembrance of Lord Viṣṇu. When one remembers Lord Viṣṇu, he becomes free from material enjoyment. Thus he gradually comes forward toward the transcendental service of the Lord and becomes eligible to chant the holy name of the Lord in the transcendental position.