कालेषु भवतीति शाश्वतः, 'शाश्वतं शिवमच्युतम्' इति श्रुतेः ।सच्चिदानन्दात्मकः कृष्णः, 'कृषिर्भूवाचकः शब्दो णश्च निर्वृतिवाचकः ।विष्णुस्तद्भावयोगाच्च कृष्णो भवति शाश्वतः' इति व्यासवचनात्; कृष्णवर्णात्मकत्वाद्वा, 'कृष्णो वर्णश्च मे यस्मात्तस्मात्कृष्णोऽहमर्जुन' इति महाभारते ।लोहिते अक्षिणी यस्येति लोहिताक्षः, 'स मा वृषभो लोहिताक्षः' इति श्रुतेः ।प्रलये भूतानि प्रतर्दयति हिनस्तीति प्रतर्दनः ।ज्ञानैश्वर्यादिगुणैः संपन्नः प्रभूतः ।ऊर्ध्वाधोमध्यभेदेन तिसृणां ककुभामपि धामेति त्रिककुब्धाम इत्येकं नाम ।येन पुनाति यो वा पुनाति ऋषिदेवता वा तत् पवित्रम् ।'पुवः संज्ञायाम्' 'कर्तरि चर्षिदेवतयोः' इति पाणिनिस्मरणात् इत्रप्रत्ययः ।'अशुभानि निराचष्टे तनोति शुभसंततिम् ।स्मृतिमात्रेण यत्पुंसां ब्रह्म तन्मङ्गलं विदुः' इति विष्णुपुराणवचनात्, कल्याणरूपत्वाद्वा मङ्गलम् ।परं सर्वभूतेभ्यः उत्कृष्टं ब्रह्म ।मङ्गलं परम् इत्येकमिदं नाम सविशेषणम् ॥
In plain words
Agrāhya (Imperceptible): because He cannot be grasped by the organs of action, as scripture says: 'From which words turn back, unable to reach Him along with the mind.' Śāśvata (Eternal): because He endures permanently across all times, as the Veda declares: 'The eternal, auspicious, immutable.' Kṛṣṇa: because His essence is existence, consciousness, and bliss, according to sage Vyāsa: 'The root kṛṣ signifies existence and ṇa signifies bliss; because of this combination, Viṣṇu is called Kṛṣṇa the Eternal'; or because of His dark complexion, as He tells Arjuna in the Mahābhārata: 'Since my color is dark, therefore I am Kṛṣṇa, O Arjuna.' Lohitākṣa (Red-eyed): having reddish eyes, as the śruti says: 'May that red-eyed bull protect me.' Pratardana (The Destroyer): because He scatters and dissolves all beings during cosmic dissolution. Prabhūta (Abundant): fully endowed with supreme knowledge, sovereignty, and other divine qualities. Trikakubdhāma: being the ultimate support and abode across the three divisions of upper, lower, and middle space. Pavitra (The Purifier): that which sanctifies or the purifier Himself, derived through Pāṇini's grammatical rules for sacred names. Maṅgala (Auspicious): as stated in the Viṣṇu Purāṇa: 'That which destroys all inauspiciousness, spreads a stream of blessing, and by mere remembrance is known by the wise to be Brahman—they know that to be Maṅgala'; or simply because His nature is supremely benign. Param: the transcendent Brahman, superior to all created beings. 'Maṅgala Param' together constitute this single qualified name.
Close to the Sanskrit
Agrāhya: because he is not grasped by the action senses, from the śruti: 'From which words turn back, failing to reach along with the mind.' Śāśvata: because he exists constantly in all times, from the śruti: 'The eternal, auspicious, immutable.' Kṛṣṇa: being of the nature of existence, consciousness, and bliss, from the statement of Vyāsa: 'The root kṛṣ denotes existence and ṇa denotes bliss; and Viṣṇu is called Kṛṣṇa Śāśvata because of the combination of those two states'; or due to having a dark complexion, from the Mahābhārata: 'Since my color is dark, therefore I am Kṛṣṇa, O Arjuna.' Lohitākṣa: having red eyes, from the śruti: 'May that red-eyed bull protect me.' Pratardana: because during dissolution he destroys or injures beings. Prabhūta: endowed with qualities like knowledge and lordship. Trikakubdhāma: being the abode of the three quarters divided by upper, lower, and middle. Pavitra: that which purifies or who purifies, being a rishi or devata, with the suffix itra applied by Pāṇini's rule: 'In the sense of a proper noun' and 'In the sense of an agent for rishi and devata.' Maṅgala: from the Viṣṇu Purāṇa statement: 'That which dispels inauspicious things, spreads a stream of auspiciousness, and by mere remembrance is known by mortals to be Brahman, they know as Maṅgala'; or due to having an auspicious nature. Param: Brahman, which is superior to all beings and transcendent. 'Maṅgala Param' is this single qualified name.